Physics Faculty Seminars on\ Modern Trends in Physics Research

Physics Faculty Seminars on
Modern Trends in Physics Research

Seminars start usually at 13:00 on Wednesdays
in room 16 (in front of dean's office).
Everyone is most welcome to give a talk!
Maciej Krawczyk (MK), Adam Miranowicz (AM), and Michał Banaszak (MB)
Physics Faculty of Adam Mickiewicz University
Collegium Physicum, ul. Umultowska 85, Poznań

Forthcoming talks

  1. /481/
    Date: Monday (sic!) 2019.06.24 at 13:00
    Speaker: Prof. Kong Liu
    Affiliation: Key Lab of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Science (CAS), Beijing, China
    Title: Carrier dynamics in organic and perovskite solar cells
    Chair: Prof. Marcin Ziółek
    Seminar language: English
  2. /482/
    Date: Friday (sic!) 2019.06.28 at 12:00
    Speaker: Prof. Jamal Berakdar
    Affiliation: Martin Luther Universität, Halle-Wittenberg, Germany
    Title: to be announced
    Chair: Dr Anna Dyrdał
    Seminar language: English
  3. /483/
    Date: Wednesday 2019.10.02 at 13:00
    Speaker: Dr Thomas B. Bahder
    Affiliation: Program Manager, Physics Division Army Research Office, Tokyo, Japan
    Title: Topological Quantum Sensors?
    Chair: Prof. Adam Miranowicz
    Seminar language: English

Former talks

  1. /480/
    Date: Wednesday 2019.06.12 at 13:00
    Speaker: Dr Thomas Vasileiadis
    Affiliation: Fritz Haber Institute of the Max Planck Society, Berlin, Germany
    Title: Ultrafast Energy Flow and Structural Changes in Nanoscale Heterostructures
    Abstract: A central goal of nanotechnology is the precise synthesis of nanostructures with optimized functionalities. The functionalities of nanostructures are controlled by external stimuli such as pulses of light, current or heat. This brings up the question: what is the connection between nonequilibrium conditions and structural stability at the nanoscale? To answer this question, we employ femtosecond electron diffraction [1] to study ultrafast energy flow and structural changes in heterostructures of size-selected Au923 nanoclusters, or Au nanoislands, on semiconducting thin-films. Au923 nanoclusters are found to exhibit ultrafast surface premelting at atypically low lattice temperatures and pronounced electron-lattice nonequilibrium conditions [2]. Furthermore, the phonons of a crystalline substrate (graphene) scatter on the adsorbed Au923 nanoclusters and induce nanocluster-rotations at picosecond timescales [3]. Finally, surface decoration with plasmonic, quasi-2D Au nanoislands sensitizes the semiconducting WSe2 to sub-band-gap photons and accelerates its electron-phonon equilibration times. All the above phenomena are considered important for the stability of nano-catalysts and the efficiency of plasmonic solar cells. This research stemmed from an international collaboration between the research group Structural Electronic Surface Dynamics headed by Ralph Ernstorfer (FHI Berlin) and the groups of Richard Palmer (Swansea University in UK), Laurenz Rettig (FHI Berlin), Vlasios Mavrantzas (ETH Zurich and University of Patras) and Stephanie Reich (Free University of Berlin).

     [1] Lutz Waldecker et al., Journal of Applied Physics 117, 044903 (2015).
     [2] Thomas Vasileiadis et al., ACS Nano 12 (8), 7710-7720 (2018).
     [3] Thomas Vasileiadis et al., Nanoscale Horizons (2019).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  2. /479/
    Date: Thursday 2019.06.06 at 13:00
    Speaker: Dr Hong-Bin Chen
    Title: Process nonclassicality: Characterization, canonical Hamiltonian ensemble representation, and quantification
  3. Authors: Hong-Bin Chen (1), Ping-Yuan Lo (2), Clemens Gneiting (3), Joonwoo Bae (4), Yueh-Nan Chen (1), and Franco Nori (3,5)
    (1) Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
    (2) Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
    (3) Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
    (4) School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
    (5) Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
    Abstract: The characterization, explanation, and quantification of quantumness, in particular the discrimination from classicality in terms of classical strategies, lie at the heart of quantum physics. Recently, it is shown that dynamical processes can exhibit classical or nonclassical traits, depending on the nature of the system-environment correlations and the related (im)possibility to simulate these dynamics with Hamiltonian ensembles - the classical strategy. Here we propose to extend this classification towards quantifying the nonclassicality. In the spirit of Wigner function, we generalize Hamiltonian ensembles to encompass quasi-probability distributions comprising negative values. Based on Lie algebra representations, Fourier transforms on groups, and root space decompositions, we demonstrate that quasi-probability distributions are faithful representations of pure dephasing dynamics; moreover, we show how to retrieve these quasi-probability distributions. This allows us to quantify process-nonclassicality time-independently, in terms of the deviations of the corresponding quasi-probability distributions from legitimate (non-negative) probability distributions.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  4. /478/
    Date: Friday 2019.05.31 at 11:00
    Speaker: Prof. Maciej Kozak
    Affiliation: Department of Macromolecular Physics, Faculty of Physics, AMU
    Title: NCPS Solaris and current status of SOLCRYS beamline
    Abstract: NCPS Solaris is a modern, low emittance synchrotron radiation source based on the storage ring (1.5 GeV) built in Double-Bend Achromat technology. The facility since 2017 is open for users, and currently offering two beamlines - ultra angle-resolved photoemission spectroscopy (UARPES) and PEEM/XAS. Next two beamlines (XMCD and XPS) are in construction or installation phase. The plans for the development of the NCPS include the construction of further beamlines. Currently, in cooperation with JINR Dubna, the design works for a modern beamline – SOLCRYS, dedicated for diffraction studies and small-angle X-ray scattering have been initiated. SOLCRYS beamline will utilize a superconducting multipole 4-Tesla wiggler as the efficient X-ray source (up to 25 keV). The synchrotron radiation beam from the source will be divided into two independent branches. During the seminar the details of the project and recent results of numerical simulations of X-ray optics for both branches, carried out using the ray-tracing method will be presented.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  5. /477/
    Date: Tuesday 2019.05.21 at 13:00
    Speaker: Prof. Taksu Cheon
    Affiliation: Laboratory of Physics, Kochi University of Technology, Tosa Yamada, Kochi, Japan
    Title: Introduction to opinion dynamics
    Abstract: Majority rule is a ubiquitous principle of collective decision making in social animals from bee to human. Despite its apparent simplicity, there are many paradoxical phenomena in democratic majority rule, such as the persistence of powerful dominating minority and majority-assisting function of contrarian opponents. In this talk, I introduce “opinion dynamics”, which has been developed in search of a mathematical model describing the realistic features of majority rule. We detail its structure, mathematical properties and predictions.
    Ref: arXiv:1901.09622 . Slides for the talk are here. 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  6. /476/
    Date: Monday 2019.05.20 at 11:00
    Speaker: Prof. Taksu Cheon
    Affiliation: Laboratory of Physics, Kochi University of Technology, Tosa Yamada, Kochi, Japan
    Title: Some aspects of quantum graph theory
    Abstract: The quantum graph is a concept describing a system of quantum particles on graphs made up of lines and vertices. It is a mathematical and solvable model of nano wire-based and quantum dot-based single-electron devices. We point out the existence of several intriguing nontrivial features of quantum graphs such as threshold resonance and controlled spectral filtering of quantum flux, and discuss their application in modeling and designing of quantum devices.
    Ref: arXiv:1203.6555 . Slides for the talk are here. 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  7. /475/
    Date: Monday 2019.05.20 at 10:00
    Speaker: Prof. Shinichiro Sakikawa
    Affiliation: International Relations Center, Kochi University of Technology, Tosa Yamada, Kochi, Japan
    Title: Research cooperation with Kochi University of Technology
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  8. /474/
    Date: Wednesday 2019.05.15 at 13:00
    Speaker: Dr Nicholas Sedlmayr
    Affiliation: Department of Physics and Medical Engineering, Rzeszów University of Technology
    Title: The Superconductivity of Topologically Protected Surface States
    Abstract: The superconducting proximity effect induced in materials in close contact with a superconductor is well established. We reveal that similarly the topologically protected surface states recently found on the surfaces of special crystals can leak into appropriate adjoining materials. We bring these two effects into proximity and study how superconductivity and topologically protected surface states interact with each other, a situation of interest in the search for Majorana bound states. We look at the scanning tunneling microscopy of a large topological insulator with superconducting islands deposited on the surface, and analyze theoretical models which capture the hybridization between the topological surface states and the superconducting states. The density of states of both the topological insulator and the superconductor turn out to exhibit interesting proximity effects and open up new possibilities for observing Majoranas.
    Chair: Prof. Ireneusz Weymann
    Seminar language: English
  9. /473/
    Date: Wednesday 2019.04.17 at 13:00
    Speaker: Dr Konrad J. Kapcia
    Affiliation: Department of Computational Materials Science, Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
    Title: Exact phase diagram of the infinite-dimensional extended Falicov-Kimball model
    Abstract: The Falicov-Kimball model [1] is a simplified version of the Hubbard model [2], where only electrons with, e.g., spin down are itinerant and the other are localized. During the seminar, we will discuss results for the extended Falicov-Kimball model at half-filling on the Bethe lattice in the limit of large dimensions derived within the DMFT formalism [3-7], which is a rigorous approach in this limit. The on-site and the intersite density-density interactions between particles occupying neighboring sites are included in the hamiltonian [5-7]. We determined the exact phase diagrams of the model both in the ground state [6] and at finite temperatures [7]. Using analytical formulas we showed that in the ground state the system is an insulator for any non-zero values of the interaction couplings and we detected the discontinuous transition between two different charge-ordered phases [6]. The finite temperature diagrams are a generalization of the diagram previously obtained in Ref. [4] for the standard Falicov-Kimball model, but they are much richer than it. In particular, it turns out that these diagrams contain more types of ordered phases, both conductive and insulating, and phase transitions between them are either continuous or discontinuous [7]. What is more, it turns out that in a certain range of interaction parameters the order-disorder phase transition may be discontinuous.

    [1] L.M. Falicov, J.C. Kimball, Phys. Rev. Lett. 22, 997 (1969); R. Ramirez, L.M. Falicov, J.C. Kimball, Phys. Rev. B 2, 3383 (1970).
    [2] J. Hubbard, Proc. R. Soc. London, Ser. A 276, 238 (1963).
    [3] J.K. Freericks, V. Zlatic, Rev. Mod. Phys. 75, 1333 (2003); A. Georges, G. Kotliar, W. Krauth, M.J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996).
    [4] R. Lemański, K. Ziegler, Phys. Rev. B 89, 075104 (2014); S.R. Hassan, H.R. Krishnamurthy, Phys. Rev. B 76, 205109 (2007).
    [5] P.G.J. van Dongen, D. Vollhardt, Phys. Rev. Lett. 65, 1663 (1990); P.G.J. van Dongen, Phys. Rev. B 45, 2267 (1992).
    [6] R. Lemański, K.J. Kapcia, S. Robaszkiewicz, Phys. Rev B 96, 205102 (2017).
    [7] K.J. Kapcia, R. Lemański, S. Robaszkiewicz, preprint, arXiv: 1903.08092 (2019).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  10. /472/
    Data: środa 2019.04.10, godz. 13:00
    Prelegent: Dr Aneta Woźniak-Braszak
    Afiliacja: Zakład Fizyki Wysokich Ciśnień, WF UAM
    Tytuł: Technika NMR poza rezonansem jako metoda do badania wolnych ruchów molekularnych w układach homo- i heterojądrowych
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  11. /471/
    Date: Wednesday 2019.04.3 at 13:00
    Speaker: Dr hab. Michał Michałowski
    Affiliation: Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University in Poznan
    Title: The discovery of a hot cocoon around an exploding supernova
    Abstract: I will present the results of observations (including those with PST2/RBT) of a gamma-ray burst (GRB) 171205A and the associated supernova (SN) 2017iuk, which led to the discovery of a hot gas cocoon. This was possible because observations started very early and the jet emission was weak. This gives support to the theoretical models of GRB/SN explosions, which predicted the existence of such a cocoon. This discovery opens the possibility to study internal processes during explosions of very massive stars, and hence will shed light on the understanding of the production of heavy elements.
    Chair: Prof. UAM Agnieszka Kryszczyńska
    Seminar language: English
  12. /470/
    Date: Thursday 2019.03.28 at 14:00
    Speaker: Prof. Vladislav E. Demidov
    Affiliation: Institute for Applied Physics and Center for Nanotechnology, University of Muenster, Germany
    Title: Excitation and amplification of coherent spin waves by spin currents
    Abstract: In this talk, I review our recent experiments on utilization of pure spin currents created by the spin-Hall effect and the nonlocal spin injection for excitation and manipulation of coherent propagating spin waves in magnonic nano-structures based on metallic and insulating magnetic films. I show that spin currents enable novel functionalities of magnonic devices not achievable by using traditional approaches. In particular, spin currents allow highly efficient excitation of continuous spin waves and short spin-wave packets with the duration down to a few nanoseconds exhibiting nonlinear self-stabilization during propagation. These demonstrations open a route for implementation of high-speed magnonic devices characterized by high information flow capacity.

    [1] V. E. Demidov et al., Nat. Commun. 7, 10446 (2016).
    [2] V. E. Demidov et al., Phys. Rep. 673, 1 (2017).
    [3] B. Divinskiy et al., Adv. Mater. 30, 1802837 (2018).
    [4] M. Evelt et al., Phys. Rev. Appl. 10, 041002 (2018).
    Chair: Prof. Sławomir Mielcarek
    Seminar language: English
  13. /469/
    Date: Wednesday 2019.03.27 at 13:00
    Speaker: Dr Anna Dyrdał
    Affiliation: Mesoscopic Physics Division, Faculty of Physics, Adam Mickiewicz University in Poznan and Institut für Physik, Martin-Luther Universität Halle-Wittenberg, Germany
    Title: Non-equilibrium spin-orbit driven phenomena in two-dimensional systems (habilitation seminar)
    Abstract: Spin-orbit interaction leads to the mixing of orbital and spin degrees of freedom and is responsible for a variety of spin and transport phenomena such as anisotropic magnetoresistance, anomalous and spin Hall effects, non-equilibrium spin polarization and spin-orbit torques. Recently under special attention are two non-equilibrium effects responsible for the efficient spin-to-charge conversion: the spin Hall effect and current-induced spin polarization. Both of them opens a unique possibility of pure electrical control of the spin degree of freedom and have been already used as an effective tool for the generation and detection of spin currents and the so-called spin-orbit torques. The physics that stands behind such effects is very rich and depends on the nature of spin-orbit coupling in the host material. Importantly, the spin-orbital effects are strongly enhanced in low-dimensional structures where the lack of inversion symmetry leads to large Rashba effect. Thus, the natural platforms for spin-orbitronics are the interfaces of semiconductor heterostructures, surfaces of topological insulators, two-dimensional van der Waals heterostructures, and perovskite-oxides heterointerfaces.

    During this seminar, I will discuss and summarize results that I obtained within the research on spin-to-charge conversion in semiconductor heterostructures and graphene-like hybrid structures. I will focus on the behaviour of spin Nernst and spin Hall effect beyond the zero-temperature limit in a two-dimensional electron gas that might appear in semiconductor heterostructures. Next, I will summarize the properties of anomalous, spin and valley Hall effects in graphene-based hybrid structures. Then, I will present results obtained for electrically and thermally induced non-equilibrium spin polarization in such systems. During the presentation, I will mention about such aspects as the interplay between effective exchange field and spin-orbit interaction, and the role of a Berry phase in the system responses. In the last part of the seminar, I will also briefly discuss the fingerprints of spin-orbit driven phenomena in the magnetoresistance effects.
    Chair: Prof. Michał Banaszak
    Seminar language: English
  14. /468/
    Data: środa 2019.03.20, godz. 13:00
    Prelegent: Dr Andrzej Ptok
    Afiliacja: Instytut Fizyki Jądrowej PAN w Krakowie
    Tytuł: Stany związane Majorany – realizacja oraz manipulacja
    Streszczenie: W układach o niskiej wymiarowości mogą być indukowane stany związane o zerowej energii, zwane stanami Majorany [1]. Obecne eksperymenty, w układzie ferromagnetycznych atomów na powierzchni nadprzewodnika [2] lub nanostruktur hybrydowych półprzewodnik—nadprzewodnik [3], potwierdzają istnienie tych stanów. Ze względu na swoje topologiczne własności, wierzy się, że stany Majorany mogą być wykorzystane do budowy kwantowych komputerów. Podczas wystąpienia przedstawię wyniki eksperymentalne pokazujące realizację stanów związanych Majorany. Omówię podstawowe własności quasi-cząstek Majorany na przykładzie układzie kropki kwantowej połączonej z nanodrutem [4]. Ze względów praktycznych, istotne jest aby w sposób kontrolowany wytwarzać stany Majorany oraz w prosty sposób nimi manipulować – zaprezentuje w jaki sposób stany te mogą być ”wytwarzane” w układzie półprzewodnikowego nieopierścieniana z kropką kwantową [5] oraz układzie ultra-zimnych gazów fermionowe w pułapce optycznej [6].

    [1] A. Y. Kitaev, Phys.—Usp. 44, 131(2001).
    [2] S. Jeon, Y, Xie, J. Li, Z. Wang, B. A. Bernevig and A. Yazdani, Science 358, 772 (2017).
    [3] V. Mourik, K. Zuo, S. M. Frolov, S. R. Plissard, E.P.A.M. Bakkers L.P. and Kouwenhoven, Science 336, 1003 (2012).
    [4] A. Ptok, A. Kobiałka and T. Domański, Phys. Rev. B 96, 195430 (2017).
    [5] A. Ptok, A. Cichy and T. Domański, J. Phys.: Condens. Matter 30, 355602 (2018).
    [6] A. Kobiałka and A. Ptok, J. Phys.: Condens. Matter 31, 185302 (2019).
    Prowadząca: Dr Agnieszka Cichy
    Seminar language: Polish
  15. /467/
    Date: Wednesday 2019.03.13 at 13:00
    Speaker: Dr Bartłomiej Graczykowski
    Affiliation: Zakład Biofizyki Molekularnej, WF UAM
    Title: Phonon transport in quasi two-dimensional nanostructures (habilitation seminar)
    Abstract: The aim of the presented research was to investigate the GHz-THz phonon propagation in quasi two-dimensional materials of importance for future emerging applications by means of developed and dedicated experimental techniques. I have investigated several strategies to tailor the phonon dispersion and the phonon MFP. In particular, these were: spatial 1D confinement, periodic patterning, implementation of local resonances, static stress and dense grain boundaries. The key scientific questions which I have considered are summarized by the following objectives: (a) To determine the influence of spatial confinement and static stress on the hypersonic phonon propagation and intrinsic elastic properties for the crystalline ultra-thin membranes. (b) To investigate the breakdown of bulk elastic properties under 1D spatial confinement and with dense grain boundaries. (c) To investigate the role of sub-micrometer periodic repetition of motifs as holes and pillars in/on Si membranes in hypersonic phonon dispersion. (d) To investigate the reduction of the thermal conductivity and its temperature dependence in holey PnCs at high temperatures (300-1000 K). (e) To quantify air-mediated heat dissipation (losses) in holey PnCs. (f) To determine the role of the structure imperfection as the surface roughness, fabrication precision and intentional disorder on the coherent (wave-like) effects in membrane based PnCs.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  16. /466/
    Date: Wednesday 2019.03.6 at 11:00
    Speaker: Prof. Deji Akinwande
    Affiliation: Microelectronics Research Center, The University of Texas at Austin, Austin, USA
    Title: Adventures with 2D Materials: From Flexible Devices to Atomic Memories and Electronic Tattoo Sensors
    Chair: Dr hab. Maciej Wiesner
    Seminar language: English
  17. /465/
    Data: środa 2019.02.27, godz. 13:00
    Prelegent: Dr hab. Wojciech Florek
    Afiliacja: Zakład Fizyki Komputerowej, WF UAM
    Tytuł: Sfrustrowane geometrycznie skończone układy spinowe: degeneracja, chiralność, dwudzielność
    (Geometrically frustrated finite spin systems: degeneration, chirality, bipartiteness)
    - seminarium profesorskie
    Streszczenie: W badaniach sfrustrowanych układów izingowskich przyjmuje się, że jednym z istotnych efektów jest wysoka degeneracja stanu podstawowego. Podobnie w przypadku (skończonych) układów kwantowych O. Kahn podkreślał znaczenie degeneracji wprowadzając termin „degenerate frustration”. Synteza i badanie sfrustrowanych geometrycznie molekuł magnetycznych wskazało, że możliwe jest występowanie układów, w których frustracji geometrycznej nie towarzyszy degeneracja stanu podstawowego. Co więcej, nie jest to li tylko efekt skończoności układu (dyskretności widma hamiltonianu), gdyż w wielu przypadkach to zachowanie jest uniwersalne: nie zależy od rozmiaru układu (liczby spinów) i wartości momentów magnetycznych (liczb spinowych). W omawianych badaniach analizowane są trzy klasy molekuł tego typu. W każdym przypadku jako podstawowy rozpatrywany jest izotropowy model Heisenberga, a jednocześnie analizowane są jego analogi: model klasyczny i model Isinga. Każdy z tych modeli ma swoje specyficzne właściwości, jednak wspomniany powyżej efekt występuje we wszystkich trzech przypadkach.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  18. /464/
    Date: Thursday 2019.02.21 at 12:00
    Speaker: Dr Susmita Saha
    Affiliation: Department of Materials, ETH Zurich, Zurich, Switzerland and Paul Scherrer Institut, Villigen, Switzerland
    Title: Skyrmion Confinement and Damping Modulation in Magnetic Thin Films
    Abstract: Magnetic skyrmions [1, 2] are topologically protected nanometer sized chiral spin textures with an out of plane magnetic domain at the center. Due to their various unique features such as stability given by their topology, they are considered as potential candidates for information carriers in next generation data storage devices, like racetrack memory. For such applications, it is crucial to be able to manipulate their current-induced motion in various directions. In this work, we present stable nanoscopic skyrmions confined by an array of antidots. Utilizing the induced periodic potential of the antidot lattice, we propose a method for unprecedented control of the skyrmion dynamics. But for that purpose it is also important to understand and control the damping in ferromagnetic thin films. One of the possible ways to manipulate magnetic damping is injection of spin current generated due to spin Hall effect [3] which is an emerging phenomenon where the properties of electrical charge current can be transferred to the electron’s intrinsic angular momentum (spin current), and vice versa. To measure the modulation of damping, we use a time-resolved magneto-optical Kerr effect microscope (TR-MOKE), which has the best spatial and temporal resolution to measure the damping of the ferromagnetic film. The observations will have a strong impact on the development of spintronics devices, such as spin transfer torque nano-oscillators or domain wall racetrack memories.
    Acknowledgement: We acknowledge ETH Zurich Post Doctoral fellowship and Marie Curie actions for People COFUND program and Dr. S. Wintz, Dr. N. S. Bingham, Dr. A. K. Suszka and Mr. T. P. Dao for technical support and valuable discussions.
     [1] D. A. Gilbert et. al., Nat. Commun. 6, 8462 (2015).
     [2] O. Boulle et. al., Nat. Nanotech. 11, 449 (2016).
     [3] L. Liu et. Al., Science, 336, 555 (2012).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  19. /463/
    Date: Wednesday 2019.02.20 at 13:00
    Speaker: Prof. Nelson Darkwah Oppong
    Affiliation: Ludwig-Maximilians-Universität München and Max-Planck-Institut für Quantenoptik
    Title: Exploring impurity physics with two-orbital quantum gases
    Abstract: Interactions of impurities with their environment govern many interesting quantum many-body phenomena in condensed matter systems, for example the Kondo effect. In particular, ultracold atoms provide an excellent platform for studying impurity physics due the precise control and independent tunability of experimental parameters. While impurities in single-orbital ultracold quantum gases have been studied, multi-orbital systems have not yet been explored. Fortunately, alkaline-earth(-like) atoms (AEAs), such as ytterbium and strontium, feature a metastable electronic state, which is long-lived and can be utilized as an orbital degree of freedom. This so-called clock state makes AEAs promising candidates for the implementation of two-orbital physics. In our experiment, we use fermionic ytterbium-173 to realize and probe impurities in two-orbital many-body systems.
    First, I report on our recent efforts to implement Kondo physics in state-dependent optical lattices. We demonstrate orbital dependent mobility in these lattices and show that interorbital spin exchange, comparable to the coupling in the Kondo model, is present in this system.
    Second, I discuss our most recent results on the observation of multi-orbital polarons in a two-dimensional Fermi gas. We precisely characterize these long-lived quasiparticles which are formed by mobile impurities interacting with a Fermi sea.
    Chair: Dr Agnieszka Cichy
    Seminar language: English
  20. /462/
    Date: Wednesday 2019.02.13 at 13:00
    Speaker: Dr Kosma Szutkowski
    Affiliation: Centrum NanoBioMedyczne UAM, Poznań
    Title: Physical insights in selected macromolecular and self-assembling systems from translational dynamics studied by Nuclear Magnetic Resonance techniques (habilitation talk)
    Abstract: Translational dynamics in soft-matter systems is related to spatial translations of atoms or molecules. Those translations can be accurately measured using Nuclear Magnetic Resonance spectroscopy given that the motion of nuclear spins is associated with a change of the magnetic field followed by a shift in the Larmor precession frequencies. We utilise the fact that the variations of the magnetic field can be either a feature of the system (local magnetic field inhomogeneities) or can be generated on purpose, using artificially created magnetic field gradient (spin labelling). In this talk, several unique applications of Nuclear Magnetic Resonance spectroscopy to translational dynamics problems in macromolecular and self-assembling systems will be presented. In particular, the following topics will be discussed: (a) self-diffusion studied for star-polymers in melt (1H PGSE NMR), (b) real-time self-diffusion experiments based on the magnetization grating (1H OUFIS single-shot diffusion NMR), (b) two-site proton hopping via hydrogen bonds upon aggregation of surfactants in aqueous solutions (1H CPMG T2 dispersion NMR), (c) an impact of interactions between BSA and Gemini surfactants on self-diffusion coefficients (1H PGSE NMR), (d) an impact of aggregation of peptides on self-diffusion coefficients (1H PGSE NMR), (e) concentration-dependent aggregation of Gemini surfactants observed via self-diffusion coefficients (1H Bayesian-DOSY NMR), (f) peptides snorkeling in micellar environments and its impact on the internal translational dynamics of surfactants in micelles (31P CPMG T2 dispersion NMR, 1H/2H/31P PGSE NMR).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  21. /461/
    Data: poniedziałek 2019.02.11, godz. 12.00
    Prelegent: Dr hab. Gotard Burdziński
    Afiliacja: Zakład Elektroniki Kwantowej, WF, UAM
    Tytuł: Mechanizm dezaktywacji fotowzbudzonych betalain i 3H-naftopiranów (Seminarium profesorskie)
    Streszczenie: Betalainy to betaksantyny i betacyjaniny stanowiące ważną grupę barwników naturalnych, występujących w roślinach z rzędu Caryophyllales, a także w niektórych grzybach wyższych. Naszym celem badawczym był opis właściwości fotofizycznych tych barwników na podstawie wyników czasowo-rozdzielczej spektroskopii absorpcji przejściowej w zakresie UV-vis-NIR. Wyznaczone czasy życia betalain w stanie S1 w roztworach wodnych i alkoholowych są krótkie (w przybliżeniu 10 ps u betacyjanin i 50 ps u betaksantyn w wodzie). Układ molekularny w stanie wzbudzonym S1 osiąga punkt przecięcia stożkowego na skutek zmiany geometrii wyrażonej poprzez obrót wokół centralnych wiązań C=C i C=N. Proces konwersji wewnętrznej S1→S0 zachodzi z wysoką wydajnością kwantową ( > 96%), co świadczy o wydajnej konwersji światła na ciepło i potwierdza fotoprotekcyjną rolę betalain w roślinach.
    Drugi zakres badań dotyczył 3H-naftopiranów – związków wykazujących fotochromizm. Po raz pierwszy zastosowaliśmy czasowo-rozdzielczą spektroskopię w średniej podczerwieni do jednoznacznej identyfikacji form barwnych transoid-cis powstających w procesie fotochromowym.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  22. /460/
    Data: środa 16.01.2019, godz. 13.00
    Prelegenci: Dr Bartłomiej Guzowski i Dr inż. Roman Gozdur
    Afiliacja: Katedra Przyrządów Półprzewodnikowych i Optoelektronicznych, Politechnika Łódzka
    Tytuł: Magnetokaloryczne konwertery energii
    Streszczenie: Koszty energii stale rosną i dlatego też prowadzi się wiele prac badawczych związanych z jej pozyskiwaniem ze źródeł odnawialnych oraz jej odzyskiwaniem (ang. energy harvesing). Termoelektryczne konwertery energii, zwane też termogeneratorami (TEG) są rozwiązaniem, które umożliwia wytworzenie energii elektrycznej z traconej energii cieplnej. Termogeneratory pracują w oparciu o powszechnie znane efekty: Seebecka, Thomsona i Peltiera i posiadają szereg zalet brak ruchomych części, brak wibracji, niezawodność i możliwość miniaturyzacji. Sprawność klasycznych TEG zależy przede wszystkim od przewodności termicznej i rezystywności elektrycznej materiałów, z których są one zrobione i jest ona niższa niż w przypadku innych typów konwersji energii [1]. Dlatego też prace badawcze koncentrują się przede wszystkim na poprawie figure of merit materiałów termoelektrycznych. Zbyt mała sprawność klasycznych TEG sprawiła, że obecnie trwają pracę nad rozwojem nowej generacji układów TEG opartych o konwertery magnetokaloryczne. Koncepcje zaprezentowane przez [2] są bardzo interesujące z punktu widzenia współczesnej elektroniki. Wprowadzenie spinowych koców termoelektrycznych [3] bezpośrednio do obudów układów elektronicznych może rozwiązać problem rosnącego wytwarzania ciepła w elementach elektronicznych. Zalety, takie jak bardzo małe rozmiary konwerterów magnetokalorycznych, możliwość ich miniaturyzacji, potencjalnie wyższy wskaźnik figure of merit w porównaniu do klasycznych TEG, czynią konwertery magnetokaloryczne bardzo interesującymi w kontekście wytwarzania energii elektrycznej z energii cieplnej. W niniejszej prezentacji omówione zostały współczesne rozwiązania związane z konwersją energii cieplnej na energię elektryczną. Zaprezentowano rozwój klasycznych TEG oraz prace badawcze związane z dalszym wzrostem ich efektywności. W dalszej części prezentacji omówione zostały termogeneratory działające w obszarze spin caloritronics oraz wykazano ich potencjalną przewagę nad klasycznymi rozwiązaniami.
    [1] A. Shakouri, Annu. Rev. Mater. Res., 41, (2011), 399–431.
    [2] A. A. Kovalev and Y. Tserkovnyak, Solid State Commun., 150, (2010), 500–504.
    [3] A. Kirihara, et. al., Nat. Mater.,11, (2012), 686–689.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  23. /459/
    Date: Wednesday 2019.01.9 at 13:00
    Speaker: Prof. Serhii Reshetniak
    Affiliation: Department of General and Experimental Physics, National Technical University of Ukraine Ïgor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
    Title: Refraction and reflection of spin waves in inhomogeneous magnetic media
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  24. /458/
    Date: Thursday 06.12.2018
    Speaker: Dr Hubert Głowiński
    Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, Poznań
    Title: Magnetization damping in polycrystalline CoFe films
    Abstract: Magnetization damping of polycrystalline thin films of the Co25Fe75 alloy was found to be very low reaching 1×10−3 and the intrinsic damping of this alloy is even lower achieving 5×10−4. Our study focuses on the influence of an adjacent layer on total damping. We found that only using Cu buffer we obtain low magnetization damping and we confirmed low value of intrinsic damping.
    Chair: Dr hab. Aleksandra Trzaskowska
    Seminar language: English
  25. /457/
    Date: Thursday 06.12.2018
    Speaker: Dr Emerson Coy (invited speaker)
    Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, Poznań
    Title: High temperature magneto dielectric thin films with low magnetic damping
    Abstract: Here we present multiferroic (ferromagnetic/ferroelectric) thin films of highly strained Bi(Fe0.5Mn0.5)O3 as the only known high-temperature magnetodielectric material with low Gilbert damping. We present the general functional properties of the material, as well as few previously unreported structural and functional properties. Finally, we will show the great potential of this perovskite for spintronic applications.
    Chair: Dr hab. Aleksandra Trzaskowska
    Seminar language: English
  26. /456/
    Date: Thursday 06.12.2018
    Speaker: Dr Żaneta Świątkowska-Warkocka
    Affiliation: Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
    Title: Laser synthesis of composite magnetic particles
    Abstract: Iron or nickel and their oxide nanoparticles have received considerable attention due to their applications in magnetic, electronic, pigmental, catalyst and biomedical purposes. NiO/Ni and Fe3O4/FeO composite particles were prepared by a pulsed laser irradiation of oxide nanoparticles dispersed in liquid. The sizes of particles and their composition were controlled by tuning the laser parameters, such as laser fluence and/or irradiation time. Correlation between structure of obtained composites and their magnetic properties will be presented.
    Chair: Dr hab. Aleksandra Trzaskowska
    Seminar language: English
  27. /455/
    Thursday 06.12.2018
    Speaker: Dr Gabriel D. Chaves-O'Flynn
    Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, Poznań
    Title: Thermal Stability of Soft Ferromagnetic Nanorings
    Abstract: The thermal stability of ferromagnetic nanostructures is mostly determined by the height of the energy barrier between two micromagnetic configurations: a metastable state and the ground state. Few analytical models for the magnetization profile at the lowest barrier have been obtained. In this talk, I will present micromagnetic simulations perform to validate one of those cases: a model for magnetization reversal of ferromagnetic nanorings [1].
    [1] Phys. Rev. B 73, 054413 (2006)
    Chair: Dr Paweł Gruszecki
    Seminar language: English
  28. /454/
    Date: Thursday 06.12.2018
    Speaker: M.Sc. Szymon Mieszczak
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Driving magnetization dynamics in an ondemand magnonic crystal via the magnetoelastic interaction
    Abstract: Using spatial light interference of ultrafast laser pulses we impulsively generate a spatial modulation of the magnetization profile in an otherwise uniformly magnetized film, inducing the onset of magnonic bandstructure and its unique spatial distribution of magnetic excitations. The magnonic behaviour is visualized by the resonant interaction of these spin wave modes with elastics waves, which are simultaneously generated with, and phase-locked to, the magnonic profile. Calculation of the spin wave modal distribution in a laterally modulated magnetization landscape, using both the Plane Wave Method and micromagnetic simulations, provide a unified picture of the non-trivial precessional dynamics observed in our experiment.
    Chair: Dr Paweł Gruszecki
    Seminar language: English
  29. /453/
    Date: Thursday 06.12.2018
    Speaker: Dr Piotr Graczyk (invited speaker)
    Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, Poznań
    Title: Electric-field-driven enhancement of magnetization dynamics in magnetoelectric heterostructures
    Abstract: We performed simulations of coupled charge-spin-magnetization dynamics in magnetoelectric heterostructure which consists of two high-permittivity dielectrics separated by two conducting ferromagnetic layers. The layers are magnetized either parallel or antiparallel to each other. We show that it is possible to affect magnetization dynamics with an ac voltage applied to such heterostructure. The effect is driven by the field-like and anti-damping spin transfer torques.
    Chair: Dr Paweł Gruszecki
    Seminar language: English
  30. /452/
    Date: Thursday 06.12.2018
    Speaker: Dr Paweł Gruszecki
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Reflection of spin wave beams
    Abstract: We present results of the theoretical investigation of the spin wave beam reflection off the ferromagnetic film’s edge and/or the gradually decreasing magnonic refractive index. In particular, we demonstrate the Goos-Hanchen and the mirage effects for spin waves. Furthermore, the scattering of the incident spin wave beam at the edge spin waves, which causes the excitation of secondary beams with the increased/decreased frequency, will be discussed, as well.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  31. /451/
    Date: Thursday 06.12.2018
    Speaker: Dr hab. Jarosław W. Kłos
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Hartman effect for spin waves in exchange regime
    Abstract: The Hartman effect is the wave phenomenon observed for the wave package tunneling through the barrier where the evanescent solutions exist. This effect is manifested by the saturation of group delay of tunneling wave package with increasing width of the barrier. We showed the possibility of existence of the Hartman effect for the exchange spin waves. We took into account the general Barnaś-Mills boundary conditions in order to calculate the transmission of spin wave through the anisotropy barrier.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  32. /450/
    Date: Thursday 06.12.2018
    Speaker: Prof. Igor L. Lyubchanskii (keynote speaker)
    Title: Goos-Haenchen effect at Brillouin light scattering
    Authors: Y. S. Dadoenkova (1,2), N. N. Dadoenkova (1,2), M. Krawczyk (3), I. L. Lyubchanskii (2,4)
    (1) Ulyanovsk State University, Ulyanovsk
    (2) Donetsk Institute for Physics and Engineering of the National Academy of Sciences of Ukraine
    (3) Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    (4) Faculty of Physics, V. N. Karazin Kharkiv National University, Kharkiv
    Abstract: The lateral shift of reflected light beam, known as Goos-Haenchen effect, is theoretically studied for Brillouin light scattering by acoustic phonons and spin waves for Daemon-Eshbach geometry [1].
    [1] Yuliya Dadoenkova, Nataliya Dadoenkova, Maciej Krawczyk and Igor Lyubchanskii, Goos-Hänchen effect for Brillouin light scattering by acoustic phonons, Optics Letters 43 (16), 3965 – 3968 (2018).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  33. /449/
    Date: Thursday 06.12.2018
    Speaker: M.Sc. Mateusz Zelent
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Controlled motion of skyrmions in magnonic antidot lattices
    Abstract: Magnetic skyrmions are topologically protected nano-meter sized chiral spin textures with an out of plane magnetic domain at the center. Due to their various unique features such as stability given by their topology, they are considered as potential candidates for information carriers in next generation data storage devices, like racetrack memory. Therefore, it is crucial to be able to manipulate their current-induced motion in various directions. Magnetic antidot arrays can be used as a controller for skyrmion motion by using properly designed sequences of electrical current pulses, which marks a big leap toward skyrmion based devices, like logic gates, magnonics filters or demultiplexers.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  34. /448/
    Date: Thursday 06.12.2018
    Speaker: Prof. Konstatin V. Guslienko (keynote speaker)
    Departament of Materials Physics, Faculty of Chemistry, University of the Basque Country, San Sebastian
    Title: Magnetic skyrmion stability and dynamics
    Abstract: Magnetic skyrmion is a kind of topological soliton, a non-trivial inhomogeneous magnetization texture on the nanoscale. In this talk I focus on the skyrmion stability and spin excitations in ultrathin magnetic films and cylindrical magnetic dots. The skyrmions can be stabilized due to an interplay of the isotropic and Dzyaloshinskii-Moriya exchange interactions, out-of-plane magnetic anisotropy and magnetostatic interaction.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  35. /447/
    Date: Thursday 06.12.2018
    Speaker: Dr Joachim Graefe (invited speaker)
    Affiliation: Max Planck Institute for Intelligent Systems, Stuttgart
    Title: Nanomagnetism in the X-Ray Spotlight
    Abstract: The X-ray microscopy allows the application of powerful spectroscopic techniques in length scales far smaller than possible with optical microcopy. Near Edge X-ray Absorption Fine Structure (NEXAFS) gives the possibilities to the element and chemically sensitive imaging, while X-ray Circular Magnetic Dichroism (XMCD) allows direct, highly sensitive detection of sample magnetization. These contrast mechanisms at spatial resolutions of below 15 nm, and even better-using emergent techniques like ptychography, combined with the possibility of using the time structure of synchrotron light for pump- and- probe imaging with time resolutions of <50 ps make x-ray microscopy a powerful tool.
    [1] W. Chao et al.: Nature 435 (2005) 1210.
    [2] D. A. Shapiro et al.: Nature Photonics 8 (2014) 765.
    [3] S. Woo et al.: Nature Materials 15 (2016) 501.
    [4] K. Litzius et al.: Nature Physics 13 (2017) 170.
    [5] S. Wintz et al.: Nature Nanotechnology 11 (2016) 948.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  36. /446/
    Date: Wednesday 05.12.2018
    Speaker: Miłosz Zdunek
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Investigation of magnons and phonons by BLS in bilayer substituted YIG samples We have investigated
    Abstract: Surface Acoustic Waves (SAWs) and Backward Volume Magnetostatic Spin Waves (BVMSWs) in bilayer substituted YIG (Yttrium Iron Garnet) samples. The bottom layer is characterised by in-plane magnetisation direction, while the top layer’s magnetisation direction is out-of-plane. The spectra were obtained by Brillouin Light Scattering (BLS) method for different magnetic configurations. The dispersion relations for aforementioned waves has been designated by analyzing the spectral data.
    This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).
    Chair: Prof. Sławomir Mielcarek
    Seminar language: English
  37. /445/
    Date: Wednesday 05.12.2018
    Speaker: Dr Batłomiej Graczykowski (invited speaker)
    Affiliation: NanoBioMedical Center, Adam Mickiewicz Univesity in Poznań, Poznań
    Title: Elastic properties of few nanometers thick membranes
    Abstract: The performance gain-oriented nanostructurization has opened a new pathway for tuning mechanical features of solid matter vital for application and maintained performance. Simultaneously, the mechanical evaluation has been pushed down to dimensions way below 1 µm. In this work, by means of micro-Brillouin light scattering we determine the mechanical properties, that is, Young modulus and residual stress, of polycrystalline few nanometers thick MoS2 membranes in a simple, contact-less, nondestructive manner. The results show huge elastic softening compared to bulk MoS2, which is correlated with the sample morphology and the residual stress.
    Chair: Prof. Sławomir Mielcarek
    Seminar language: English
  38. /444/
    Date: Wednesday 2018.12.05
    Speaker: M.Sc. Nandan Babu Kuttath Padi
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Authors: A. Trzaskowska, S. Mielcarek, , M. Zdunek, P. Graczyk, J. W. Kłos, and M. Krawczyk
    Title: Magnons and phonons in CoFeB/Au multilayer structures
    Abstract: Inelastic light scattering is a powerful method to study the dispersion relations of magnons and phonons. We determine the dispersion relation of thermal magnons and phonons which exist in the multilayered sample using Brillouin light scattering (BLS) spectroscopy in CoFeB/Au multilayer deposited on the silicon substrate with Ti and Au layers.In the backward scattering geometry, the dispersion relations of magnons and phonons are determined for different values of the magnetic field. The finite element method (FEM) is used for interpretation of the experimental results.
    This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).
    Chair: Prof. Sławomir Mielcarek
    Seminar language: English
  39. /443/
    Date: Wednesday 05.12.2018
    Speaker: Dr hab. Aleksandra Trzaskowska (invited speaker)
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Periodic nanostructures investigated using BLS
    Abstract: Experimental and theoretical study of the phononic band gap in the hypersonic range for thermally activated Surface Acoustic Waves will be presented. Two dimensional phononic crystals have been studied by the Surface Brillouin Light Scattering. The experimental data will be compared with results of theoretical modeling by the Finite Element Method.
    Chair: Prof. Sławomir Mielcarek
    Seminar language: English
  40. /442/
    Date: Wednesday 05.12.2018
    Speaker: M.Sc. Filip Lisiecki (invited speaker)
    Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, Poznań
    Title: Reprogrammability and scalability of magnonic Fibonacci quasicrystals
    Abstract: Magnonic quasicrystals exceed the possibilities of spin waves (SW) manipulation offered by regular magnonic crystals, because of their more complex SW spectra with fractal characteristics. Here, we show the reprogrammability property of 1D Fibonacci magnonic quasicrystals, which allows controlling the SWs transmission. We demonstrate this property in the structures of different elements sizes and thus show the scalability of this system down to the nanometer scale.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  41. /441/
    Date: Wednesday 05.12.2018
    Speaker: Grzegorz Centała
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: The effect of spin wave pinning on FMR frequency in periodic structures
    Abstract: One of the greatest advantages of spin waves is high frequency associated with low energy loss, therefore spin waves are promising as prospective information carriers. However, the usability of the devices based on spin waves is dependent on the range of operating frequency. The customizable frequency range may be achieved by changes in structural parameters, hence we consider spin wave pinning as a relatively easy way to adjust the frequency. Numerical calculations were made for CoFeB stripes arranged in the horizontal plane. We checked how the change in the width, thickness, and distance between the stripes affects the FMR frequency.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  42. /440/
    Date: Wednesday 05.12.2018
    Speaker: M.Sc. Justyna Rychły
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Theoretical studies of spin wave dynamics in planar magnonic quasicrystals
    Abstract: We have studied theoretically spin wave dynamics in planar magnonic quasicrystals and compared obtained results with the corresponding magnonic crystals. We have found that magnonic quasicrystals are characterized by complex spin wave spectra of a fractal nature and that spin waves of higher frequencies are localized in the bulk region of an intact system. Moreover, the lifetime of spin wave modes in magnonic crystals and magnonic quasicrystals will be presented.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  43. /439/
    Date: Wednesday 05.12.2018
    Speaker: Dr Paweł Sobieszczyk (invited speaker)
    Affiliation: Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
    Title: Magnetization reversal mechanisms in nanopatterned thin films with perpendicular magnetic anisotropy
    Authors: Paweł Sobieszczyk, Michał Krupiński, Piotr Zieliński, Marta Marszałek
    Abstract: Fabrication and modeling of patterned thin films with perpendicular magnetic anisotropy rise great interest due to their wide applications in magnetic storage, sensors and magnonic crystals. A good representative of such systems are well-ordered arrays of magnetic antidots and dots based on Co/Pd multilayers, where magnetic reversal mechanisms strongly depend on the array geometry [1, 2]. We attempt to understand and reproduce the observed magnetic properties and domain structure appearing in the arrays by micromagnetic simulations performed using Mumax3 software [3]. In particular, changes in coercivity field, magnetic anisotropy constant and magnetic domain arrangement were studied and correlated with symmetry and size of nanostructures. The calculations show how edge effects, defects and inhomogeneity affect magnetization reversal and domain wall pinning mechanism, which helps to design similar patterned systems with the specific magnetic properties. Acknowledgments The numerical simulations were supported in part by the PL-Grid Infrastructure.
    [1] M. Krupinski, D. Mitin, A. Zarzycki, A. Szkudlarek, M. Giersig, M. Albrecht and M. Marszałek, Magnetic transition from dot to antidot regime in large area Co/Pd nanopatterned arrays with perpendicular magnetization, Nanotechnology 2017, 28, 085302.
    [2] C. Banerjee, Pawel Gruszecki, J. W. Klos, O. Hellwig, M. Krawczyk, and A. Barman, Magnonic band structure in a Co/Pd stripe domain system investigated by Brillouin light scattering and micromagnetic simulations, Phys. Rev. B 96, 024421
    [3]Vansteenkiste, A.; Leliaert, J.; Dvornik, M.; Helsen, M.; Garcia-Sanchez, F.; Van Waeyenberge, B., The Design and Verification of Mumax3. AIP Adv. 2014, 4, 107133.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  44. /438/
    Date: Wednesday 05.12.2018
    Speaker: Krzysztof Szulc
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Magnetization reversal in the array of nanobars
    Abstract: We investigate remagnetization in the two-dimensional array of permalloy nanobars with periodic and Fibonacci order. Hysteresis loops measured with magneto-optic Kerr effect microscopy shows particular behaviour of the structure in the magnetization reversal process. Monte Carlo simulations of macrospins in effective field and micromagnetic simulations as well as theoretical investigations of demagnetizing fields and dipolar interactions complemented experimental results explaining occurent phenomenons.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  45. /437/
    Date: Wednesday 05.12.2018
    Speaker: Dr Dominika Kuźma
    Affiliation: Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
    Title: Modeling of configuration switching in systems of macrospins
    Abstract: We study switching mechanisms between ferromagnetic and antiferromagnetic (F – AF) configurations in systems of elliptically shaped flat nanoparticles (macrospins) under a variable applied magnetic field. Using a software based on the dynamical matrix method we compute frequencies and the corresponding spin profiles for the spin waves. Of special interest are those in the gigahertz frequency region. Limits of stability of configurations are marked by soft spin waves. We present various possibilities of enhancing recovery of the most stable AF configuration in a homogeneous external field.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  46. /436/
    Date: Wednesday 05.12.2008
    Speaker: Prof. Piotr Zieliński (keynote speaker)
    Affiliation: Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
    Title: Is a discontinuous phase transition of second order possible in magnetic systems?
    Authors: P. Zieliński (1,2), D. Kuźma (1), P. Sobieszczyk(1), F. Montoncello (3)
    (1) Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
    (2) Institute of Nuclear Physics, Cracow University of Technology, Kraków, Poland
    (3) Department of Physics and Earth Sciences, CNISM Unit, University of Ferrara, Ferrara
    Abstract: A transition between group-subgroup unrelated configurations is always discontinuous and often marked by a large hysteresis that impedes the switching of the configurations by varying a control parameter. This is e.g. characteristic of martensitic phase transitions. It will be shown that in some specific spin systems the hysteresis width may be reduced to zero in analogy to the second order phase transitions. Possible applications of such systems in the most efficiently switchable devices will be discussed.
    Chair: Dr hab. Jarosław W. Kłos
    Seminar language: English
  47. /435/
    Date: Wednesday 05.12.2018
    Speaker: M.Sc. Vishal Vashistha
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Light channeling, bending and splitting via local modification of interfaces of a photonic-crystal slab
    Abstract: Photonics crystal slab (PC) consists of one, two, or three dimensions periodic array structures which are widely used for many applications in photonics such as guiding the light (waveguide), high-quality factor cavity resonator, photonic crystal fibers, and so on. In general, PCs are designed by removing the certain portion of the periodic array structures so-called defect region and this defect region is used to guide the light. We study a new hybrid PC slab which consists of dielectric rods coated with a thin layer of metal cap structures, and the defect region is created by just removing the thin layer of the metal cap. In this talk, I will present the various modes which exists in the defect region, and I will present the properties of different modes while propagating the light in different shapes of the waveguide.
    Chair: Prof. Igor L. Lyubchanskii
    Seminar language: English
  48. /434/
    Date: Wednesday 05.12.2018
    Speaker: Dr hab. Maciej Wiesner (invited speaker)
    Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
    Title: Can surface plasmons break symmetry in topological insulators and graphene?
    Abstract: A monolayer graphene is a perfect material allowing for high frequency transport of electrons. Due to missing energy band gap its application in switching devices is not possible. The only way to open the band gap is symmetry breaking of a monolayer graphene.Topological insulators are famous of lack of scattering of electrons on structural defects. Topologically protected states can be observed in samples of thickness of 2 – 7 nm where contribution of bulk electrons bulk is limited. Fabrication of such thin layers requires advanced techniques like MBE. To reduce contribution of bulk electrons to surface conductivity one have to break symmetry of the topological insulator along zdirection. During this talk I will present results showing the effect of symmetry breaking in both materials due to surface plasmon generation.
    Chair: Prof. Igor L. Lyubchanskii
    Seminar language: English
  49. /433/
    Date: Wednesday 05.12.2018
    Speaker: Prof. Vasily V. Temnov (keynote speaker)
    Affiliation: Institute of Molecules and Materials of Le Mans, CNRS, Le Mans, France
    Title: Nonlinear magneto-plasmonics and Wood’s anomaly probed by magnetic second-harmonic generation
    Abstract: Angular- and wavelength-dependent magnetic second harmonic generation (mSHG) on periodic arrays of nickel nanodimers allowed us to identify a periodic structure acting as a meta-surface (diffraction forbidden) at the fundamental frequency and diffraction grating (diffraction allowed) at the double SHG frequency and observe the purely nonlinear Wood's anomaly. Similar measurements on magneto-plasmonic multilayers in Kretschmann configuration are used to quantify the nonlinear phase-matching condition and magnetic control of surface plasmon polaritons generated at the SHG frequency.
    Chair: Prof. Igor L. Lyubchanskii
    Seminar language: English
  50. /432/
    Date: Wednesday 05.12.2018
    Speaker: Prof. dr hab. Tadeusz Lulek (invited speaker)
    Affiliation: Division of Mathematical Physics, Faculty of Physics, AMU, Poznań
    Title: A three-magnon qubit: an example of Galois symmetry of Bethe pseudoparticles
    Abstract: We discuss a specific Bethe Ansatz solution [1,2] of the eigenproblem of the Heisenberg Hamiltonian for a magnetic isotropic ring with N=7 nodes, at the centre k=0 of the Brillouin zone, within the three-magnon sector r=3, which implements an arithmetic qubit with the energy E=-5, and whose the basis states are rigged string configurations. We demonstrate that this qubit exhibits Galois symmetry, represented by the dihedral group D6 permuting six admissible state parameters of r=3 Bethe pseudoparticles.
    [1] T. Lulek, M. Łabuz, J. Milewski, and R. Stagraczyński, Physica B550, 294 (2018)
    [2] J. Milewski, B. Lulek, T. Lulek, and R. Stagraczyński, Physica B434, 14 (2014).
    Chair: Prof. Igor L. Lyubchanskii
    Seminar language: English
  51. /431/
    Date: Wednesday 2018.12.05
    Speaker: Prof. Adam Miranowicz
    Title: Deterministic quantum nonlinear optics without photons
    Authors: Anton F. Kockum (1), Adam Miranowicz (1,2), Simone De Liberato (1,3), Salvatore Savasta (1,4), and Franco Nori (1,5)
    (1) Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
    (2) Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
    (3) School of Physics and Astronomy, University of Southampton, Southampton, United Kingdom
    (4) Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Universita di Messina, Messina, Italy
    (5) Physics Department, The University of Michigan, Ann Arbor, Michigan, USA
    Abstract: We show how analogs of a large number of well-known nonlinear-optics phenomena can be realized with one or more two-level atoms coupled to one or more resonator modes in the ultrastrong-coupling regime. Through higher-order processes, where virtual photons are created and annihilated, an effective deterministic coupling between two states of such a system can be created. In this way, analogs of three-wave mixing, four-wave mixing, higher-harmonic and -subharmonic generation (i.e., up- and down-conversion), multiphoton absorption, parametric amplification, Raman and hyper-Raman scattering, the Kerr effect, and other nonlinear processes can be realized. In contrast to most conventional implementations of nonlinear optics, these analogs can reach unit efficiency, only use a minimal number of photons (they do not require any strong external drive), and do not require more than two atomic levels [1,2,3].
    [1] A. F. Kockum, A. Miranowicz, V. Macri, S. Savasta, F. Nori, Phys. Rev. A 95, 063849 (2017), e-print arXiv:1701.05038 .
    [2] R. Stassi, V. Macri, A. F. Kockum, O. Di Stefano, A. Miranowicz, S. Savasta, and F. Nori, Phys. Rev. A 96, 023818 (2017), e-print arXiv:1702.00660 
    [3] A. F. Kockum, A. Miranowicz, S. De Liberato, S. Savasta, and F. Nori, in press in Nature Reviews Physics, e-print arXiv:1807.11636 .
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  52. /430/
    Date: Wednesday 05.12.2018
    Speaker: Prof. Krzysztof Grygiel
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU, Poznań
    Title: Anomalous rotational diffusion in electric fields
    Abstract: The formulae for linear electric polarization induced by harmonic electric field in liquids composed of rigid noninteracting dipolar and asymmetric-top molecules in spherical solvents are derived. The model of noninertial, anomalous rotational Brownian motion is applied. The fractional rotational diffusion equations are solved and time evolution of the electric polarizability is investigated for the case when a dc-electric field is turned off and for the stationary state case when only an ac-field is present. Numerical analysis of the dispersion and absorption parts of electric polarizability is performed as well as the influence of molecular parameters on so-called Cole-Cole plots is investigated.
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  53. /429/
    Date: Wednesday 2018.12.05
    Speaker: Dr Małgorzata Paprzycka
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU, Poznań
    Title: Raman spectroscopy for proteins – fish collagen study
    Abstract: [PDF]  Modern medicine widely uses exogenous collagen as good material for tissue regeneration, also as natural substrate for cell attachment and proliferation, used to create dressings and to support the treatment of burn wounds or diabetic wounds, or finally as a source of amino acids in the diet complementary to the body's needs [1,2]. Collagen is a safe material that has a high biocompatibility and biodegradability and good cell adhesion [3]. Due to the possibility of transferring Creutzfeld-Jacob disease(Bovine Spongiform Encephalopathy) from animals to the human body, the interest in collagen from fish increased. The collagen we examined comes from the skin of silver carp fish (Hypophtalmichthys molitrix), and was obtained by method of hydration in an aqueous lactic acid solution [4]. The topography of the test sample was made with The Dimension® Icon™ Scanning Probe Microscope (SPM), showing its fibrillar structure, with dimensions equivalent to those shown in the literature [5]. Raman spectroscopy was used to study fish collagen using a Renishaw Ramascope 1000 spectrometer. The source of the excitations was a helium-neon laser with a wavelength of 633 nm. Analysis of Raman spectra allowed to determine the content of amino acids in collagen, including glycine, proline and hydroxyproline. It also showed the native nature of the material at 200C. The durability of the secondary structure of this material heated to about 900C and cooled was also proved. Raman spectroscopy has been presented as an effective method for testing biopolymers [6].
    [1] Sanz M and all, Clinical Evaluation of a New collage matrix (mucograpf prototype) to enhance the wight of keratinized tissue In patients with fixed prosthetic restorations: a randomized prospective clinical trial. J. Clin Periodontol. 2009; 36 (10), 868-876.
    [2] Ghanaati S et al, Evaluation of the tissue reaction to a new bilayered collagen matrix in vivo and its translation to the clinic. Biomed Mater. 2011(1); 015010.
    [3] Sionkowska A. Current reaserch on the blends of natural and synthetic polymers as new biomaterial: review. Progress in Polimer science, 2011; 36: 1254-1276.
    [4] Przybylski J.E., Patent US 7285638, B2 (2007).
    [5] Buehler M.J., Nature designs tough collagen: Explaining the nanostructure of collagen fibrils, Proceedings of the National Academy of Sciences Aug 2006, 103 (33) 12285-12290.
    [6] Paprzycka M, Scheibe B, Jurga S, Fish collage – molecular structure after thermal treatment, Fibres & Textile In Eastern Europe, 132, 2018.
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  54. /428/
    Date: Wednesday 2018.12.05
    Speaker: Prof. Waldemar Głaz
    Affiliation: Nonlinear Optics Division, Physics Faculty, Adam Mickiewicz University, Poznań, Poland
    Title: Ab initio vs model extended techniques of computing linear and nonlinear collisional polarizabilities in H2-H supermolecules.
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  55. /427/
    Date: Wednesday 2018.12.05
    Speaker: Prof. Jan Peřina Jr. (keynote speaker)
    Title: Auto-ionization in the presence of a neighbor atom
    Authors: J. Peřina1, Jr., W. Leoński2, A. Luks1, V. Peřinová1
    1Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Science of the Czech Republic, Olomouc, Czech Republic
    2 Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Zielona Góra, Poland
    Abstract: Long-time photoelectron ionization spectra of a system with an auto-ionizing level interacting with a neighbor two-level atom are discussed. These spectra are typically composed of several peaks. Conditions for the occurrence of Fano and Fano-like zeros are revealed. Photoelectron ionization spectra conditioned by the measurement on the two-level atom show oscillations at the Rabi frequency of the neighbor two-level atom. The presence of spectral dynamical zeros in the conditioned spectra is predicted. Also entanglement between an ionized electron and that bound on the two-level system is analyzed using negativity. Two-dimensional spectral density of negativity is defined to identify spectrally local entanglement between two electrons. It reveals that entanglement is 'concentrated' around spectral peaks.
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  56. /426/
    Date: Wednesday 2018.12.05
    Speaker: Dr Natalia Kielich-Buchowska
    Affiliation: Faculty of Law and Administration, Adam Mickiewicz University, Poznań, Poland
    Title: Memories of Prof. Stanisław Kielich (invited talk)
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  57. /425/
    Date: Wednesday 2018.12.05
    Speaker: Prof. Ryszard Tanaś
    Affiliation: Nonlinear Optics Division, Physics Faculty, Adam Mickiewicz University, Poznań, Poland
    Title: Memories of Prof. Stanisław Kielich
    Abstract: In my talk I would like to remind some historical facts from the biography of Professor Stanisław Kielich related to the beginning and progress of nonlinear optics in Poznań.
    Chair: Prof. Krzysztof Grygiel
    Seminar language: English
  58. /424/
    Date: Tuesday 2018.12.04, 13:00
    Speaker: Prof. Jan Peřina Jr.
    Authors: Jan Peřina Jr., O. Haderka, V. Michalek, and I. I. Arkhipov
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Science of the Czech Republic, Olomouc, Czech Republic
    Title: Experimental photon counting with weak twin beams
    Abstract: Investigations of mesoscopic twin beams containing typically several photon pairs using an iCCD camera with single-photon resolution will be discussed. Operation of the camera as a photon-number-resolving detector endowed with spatial resolution will be analyzed. Different types of reconstructions of the joint signal-idler photon-number distributions of twin beams will be discussed including the method of maximal likelihood and that assuming a multimode Gaussian form of in general noisy twin beams. Also the use of spatial correlations inside twin beams for reducing the noise in the experimental data and subsequent less-noisier reconstruction of the joint photon-number distribution will be mentioned. Reconstruction of the joint signal-idler quasi-distributions of integrated intensities will be discussed. Different types of nonclassicality (entanglement) criteria written in terms of integrated-intensity moments as well as using directly the elements of photon-number distributions will be introduced. The method of absolute detector calibration principally based on pairing of photons in twin beams will be presented. Postselection by photon-number-resolving detection as a tool for generating (higher-order) sub-Poissonian states of light will be discussed based on the experimental results.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  59. /423/
    Date: Wednesday 2018.11.28
    Speaker: Dr hab. Anna Kowalewska-Kudłaszyk
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU, Poznań
    Title: Photon blockade via squeezing
    Abstract: Single photon generation can be obtained either in optical systems with strong single-photon nonlinearities (conventional photon blockade) or in the systems with extremely weak optical nonlinearities (unconventional photon blockade). Such photon blockades are associated with sub-Poissonian statistics and strong antibunching. We will discuss possibility of observing single, multiphoton and non-standard blockades with squeezed states. An example of dissipative squeezing interactions will be given.
    Chair: Dr hab. Jan Soubusta
    Seminar language: English
  60. /422/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Shilan Ismael Abo
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU, Poznań
    Title: Photon-phonon blockade
    Abstract: Many applications in quantum technologies, such as quantum cryptography or optical quantum information processing, require light sources with a precise number of photons. Photon (phonon) blockade is the quantum phenomenon that occurs in a driven nonlinear system, in which a single photon (phonon) in the system prohibits the generation or entry of other photons (phonons) to the system. These effects are described by the sub-Poissonian excitation-number statistics. Here we describe cases such that a combined photon-phonon mode exhibits sub-Poissonian statistics, while each mode, if analyzed separately, exhibits super-Poissonian statistics.
    Chair: Dr hab. Jan Soubusta
    Seminar language: English
  61. /421/
    Date: Wednesday 2018.11.28
    Speaker: Dr Ievgen I. Arkhipov
    Affiliation: Joint Laboratory of Optics of Palacky University and Institute of Physics of CAS, Olomouc, Czech Republic
    Title: Revealing nonclassicality of Gaussian states of light
    Abstract: We present a method that allows one to completely reveal nonclassicality of Gaussian states of light, initially generated in optical spontaneous parametric processes, by means of an appropriately induced stimulated emission. Namely, we exploit the fact that stimulating fields in stimulated emission processes for Gaussian states play the role of displacing coherent fields, which, therefore, by no means affect nonclassicality of initially generated Gaussian states. Then, by utilizing a certain nonclassicality criterion, which is expressed in terms of integrated intensity moments of optical fields up to the second order, we show that one can truly certify the presence of quantum correlations of such Gaussian states by varying the complex amplitude of stimulating coherent fields.
    Chair: Dr hab. Jan Soubusta
    Seminar language: English
  62. /420/
    Date: Wednesday 2018.11.28
    Speaker: Dr Karol Bartkiewicz
    Affiliations: (1) Nonlinear Optics Division, Physics Faculty, AMU, Poznań and (2) RCPTM, Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Czech Republic
    Title: Measuring distance between points in Hilbert space with photons
    Abstract: The quantum properties of polarisation-correlated photon pairs like, e.g., quantum entanglement, purity etc. make them a powerful resource in quantum communication, including quantum key distribution protocols. These properties and their quantifiers, which can be defined in terms of distances in Hilbert space, are usually measured indirectly by first performing complete quantum state tomography and then calculating their value from the reconstructed density matrices. In many cases this procedure requires performing more measurements than necessary to characterise the investigated quantum property and it tells little about the nature of the characterised property. I will explain how to directly measure the distance between points in Hilbert space using single photons, the maximal level of Bell inequality violation, a universal entanglement witness and the negativity of an arbitrary two-photon polarisation state by only two-photon interference of photons assorted from a few (at most four) copies of the investigated state. I will discuss the experimental challenges and limitations of this approach as well as the possible solutions within the framework of linear optics.
    [1] Bartkiewicz, K., Horst, B., Miranowicz, A., "Entanglement estimation from Bell inequality violation," Phys. Rev. A 88, 052105 (2013).
    [2] Bartkiewicz, K., Lemr, K., Černoch, A., Miranowicz, A, "Bell nonlocality and fully entangled fraction measured in an entanglement-swapping device without quantum state tomography," Phys. Rev. A 95, 030102R (2017).
    [3] Bartkiewicz, K., Horodecki, P., Lemr, K., Miranowicz, A., Życzkowski, K., "Method for universal detection of two-photon polarization entanglement," Phys. Rev. A 91, 032315 (2015).
    [4] Bartkiewicz, K., Beran, J., Lemr, K., Norek, M., Miranowicz, A., "Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix," Phys. Rev. A 91, 022323 (2015).
    [5] Bartkiewicz, K., Chimczak, G., Lemr, K., "Direct method for measuring and witnessing quantum entanglement of arbitrary two-qubit states through Hong-Ou-Mandel interference, " Phys. Rev. A 95, 022331 (2017).
    [6] Bartkiewicz, K., Chimczak., "Two methods for measuring Bell nonlocality via local unitary invariants of two-qubit systems in Hong-Ou-Mandel interferometers," Phys. Rev. A 97, 012107 (2018).
    [7] Bartkiewicz, K., Lemr, K., Černoch, A., Soubusta, J., "Measuring nonclassical correlations of two-photon states," Phys. Rev. A 87, 062102 (2013).
    [8] Trávníček, V., Bartkiewicz, K., Černoch, A., Lemr. K., "Experimental measurement of a nonlinear entanglement witness by hyperentangling two-qubit states," Phys. Rev. A 98, 032307 (2018).
    Chair: Dr hab. Karel Lemr
    Seminar language: English
  63. /419/
    Date: Wednesday 2018.11.28
    Speaker: Dr Antonín Černoch (invited speaker)
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Beam-splitting tricks
    Abstract: Beam-splitter is a very common component of setups for quantum information experiments. The quality of measurement results strongly depends on its parameters especially on splitting ratio. In this talk some tricks how to fine tune the splitting ratio will be shown.
    Chair: Dr hab. Karel Lemr
    Seminar language: English
  64. /418/
    Date: Wednesday 2018.11.28
    Speaker: Dr hab. Jan Soubusta (invited speaker)
    Title: Experimental testing of three-qubit nonlocality
    Authors: Artur Barasiński (1,2), Antonín Černoch (2), Karel Lemr (2), and Jan Soubusta (2)
    (1) Institute of Physics, University of Zielona Góra, Poland
    (2) Joint Laboratory of Optics of Palacky University and Institute of Physics of Czech Academy of Sciences, 771 46 Olomouc, Czech Republic
    Abstract: [PDF]  We are used to the fact that all bipartite pure entangled quantum states violate a Bell inequality. This means that measurement results on this quantum system manifest nonlocal correlations. So far the relationship between entanglement and nonlocality is still a subject of an intense study. Recently a new measure of nonlocality was proposed [1]. It is defined as the probability, that the pure state will display nonlocal correlation when subjected to random measurements. When scanning over all possible projection measurements, we can define a nonlocal volume, which corresponds to the subspace in which the projection measurements prove nonlocality of the input state. We decided to test these relations for three-qubit states, generalized Greenberger-Horne-Zeilinger (gGHZ) states [2]. It was recently shown that the nonlocal volume has very convenient properties. For example, for pure states this measure is monotonic with entanglement described by the gGHZ angle. The more the state is entangled, the larger is the probability to violate Bell inequalities selecting random measurements. For this purpose we first had to build an efficient experimental setup, that is capable to generate the gGHZ states. states and to carry out the optimal measurements very fast. Secondly, we have experimentally verified numerical simulations of optimal measurements proposed to detect the greatest violation of several Bell-type inequalities for three-partite states [3, 4]. Finally, we have started detailed experimental mapping of the projection measurement space to get the nonlocal volume of the tested states. We hope that this both theoretical end experimental research can help to get better insight into the abstract quantities characterizing quantum states and also to the mutual relationship between them [5, 6].
    [1] V. Lipinska, F. J. Curchod, A. Mattar, and A. Acin, New J. Phys. 20, 063043 (2018).
    [2] D. M. Greenberger, M. A. Horne, A. Shimony, and A. Zeilinger, Am. J. Phys. 58, 1131 (1990).
    [3] G. Svetlichny, Phys. Rev. D 35, 3066 (1987).
    [4] J.-D. Bancal, J. Barrett, N. Gisin, and S. Pironio, Phys. Rev. A 88, 014102 (2013).
    [5] I. Arkhipov, A. Barasiński, and J. Svozilik, Sc. Rep. 8, 16955 (2018).
    [6] A. Barasiński, Sc. Rep. 8, 12305 (2018).
    Chair: Dr hab. Karel Lemr
    Seminar language: English
  65. /417/
    Date: Wednesday 2018.11.28
    Speaker: Dr Grzegorz Chimczak
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU, Poznań
    Title: Four-level diamond-type atom as a field-field coupler
    Abstract: We present engineering a fully controllable effective coupling between two quantized cavity modes via an ensemble of four-level atoms in the diamond configuration. This controllable effective coupling makes it possible to transfer coherent superpositions of cavity-mode number states from one mode to the other on demand. We also show that despite the fact that the system is complex, it is possible to describe its evolution using a simple effective Hamiltonian.
    Chair: Prof. Wiesław Leoński
    Seminar language: English
  66. /416/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Mateusz Nowotarski
    Title: Entanglement properties of highly symmetric qudit states
    Authors: Mateusz Nowotarski (1) and Artur Barasiński (1,2)
    (1) Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Z. Szafrana 4a, 65-516 Zielona Góra, Poland
    (2)RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Sciences of the Czech Republic, 17. Listopadu 12, 772 07 Olomouc, Czech Republic
    Abstract: Quantum entanglement plays an important role in quantum theory as one of the most unintuitive physical phenomenons. Because of many possible applications, characterization of quantum states is an important task. While the calculation of entanglement measures for pure two-qudit states is not challenging, it becomes significantly much more complicated in case of mixed two-qudit states. The basic approach to this problem is restriction the specific subgroup of states which obey specific symmetrical conditions. Here we discus a recently introduced highly symmetric qudit states family with incomplete permutation symmetry [1, 2] This family consists of both pure and mixed states and can be described by five real parameters. For those states we perform extensive analysis of various conditions of separability and entanglement classification. Furthermore our results can be used for any arbitrary quantum state by application of twirling operator.
    [1] A. Barasiński and M. Nowotarski, Phys. Rev. A 94, 062319 (2016)
    [2] A. Barasiński and M. Nowotarski, Phys. Rev. A 95, 042333 (2017)
    Chair: Prof. Wiesław Leoński
    Seminar language: English
  67. /415/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Izabela Domagalska
    Title: The influence of a charge asymmetry of cores on the physical state of the positively charged molecule ion.
    Authors: Izabela A. Domagalska (1), Marcin W. Jarosik (2), Radosław Szczęśniak (2), Joanna K. Kalaga (1)
    (1) Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Zielona Góra, Poland
    (2) Institute of Physics, Częstochowa University of Technology, Częstochowa, Poland
    Abstract: We have analyzed the dynamics of the positively charged ion of a diatomic molecule, in which the atomic cores are under the influence of an external force of harmonic-type which is explicitly dependent on the amplitude and frequency. The ground state of the ion has been determined using the variational method. The influence of charge core asymmetry on such state energy and the filling of ion nodes has been calculated. We have also verified how the charge asymmetry of the cores affects the value of the Lyapunov exponent.
    Chair: Prof. Wiesław Leoński
    Seminar language: English
  68. /414/
    Date: Wednesday 2018.11.28
    Speaker: Dr Joanna Kalaga (invited speaker)
    Title: Generation of squeezed states in a quantum-chaotic system
    Authors: J. K. Kalaga (1,2), W. Leoński (1,2), M. W. Jarosik (3), and R. Szczęśniak (3)
    (1) Quantum Optics and Engineering Division, Faculty of Physics and Astronomy, University of Zielona Góra, Zielona Góra, Poland
    (2) Joint Laboratory of Optics of Palacký University and Institute of Physics of CAS, Faculty of Science, Palacký University, Olomouc, Czech Republic
    (3) Institute of Physics, Częstochowa University of Technology, Częstochowa, Poland
    Abstract: Analysis of quantum dynamics of the systems which classical counterparts exhibit chaotic behavior seems to be one of the most intriguing topics related to the quantum dynamics' research. In particular, finding the methods allowing detection of the appearance of the quantum chaos is especially intriguing. We consider here the application of the normally ordered variances of the quadratures operators as a witness of quantum-chaotic evolution. We discuss them in a context of the anharmonic Kerr-like oscillator excited by a series of ultra-short coherent pulses.
    Chair: Prof. Wiesław Leoński
    Seminar language: English
  69. /413/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Marcin Karczewski
    Affiliation: Quantum Electronics Division, Physics Faculty, AMU
    Title: Monogamy of Particle Statistics in Tripartite Systems Simulating Bosons and Fermions
    Abstract: In the quantum world, correlations can take the form of entanglement which is known to be monogamous. Following Phys. Rev. Lett. 121, 090403 (2018), we will argue that another type of correlation, indistinguishability, is also restricted by some form of monogamy. Namely, if particles A and B simulate bosons, then A and C cannot perfectly imitate fermions. The main point of this talk consists in demonstrating to what extent it is possible.
    Chair: Prof. Ryszard Tanaś
    Seminar language: English
  70. /412/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Zakarya Lasmar
    Affiliation: Quantum Electronics Division, Physics Faculty, AMU
    Title: On composite behaviour of complex quantum systems: sometimes entanglement needs to be backed by interaction
    Abstract: It was recently suggested that two entangled fermions can behave like a single boson and that the bosonic quality is proportional to the degree of entanglement between the two particles. The relation between bosonic quality and entanglement is quite natural if one takes into account the fact that entanglement appears in bound states of interacting systems. However, entanglement can still be present in spatially separated subsystems that do not interact anymore. These systems are often a subject of studies on quantum nonlocality and foundations of quantum physics. In the first half of this talk, I will discuss whether an entangled spatially separated fermionic pair can exhibit bosonic properties. I will consider certain conditions under which the answer to this question can be positive. In addition, I will present a nonlocal bunching scenario in which two of such pairs form an analogue of a two-partite bosonic Fock state. In the second half of this talk, I will present our new findings regarding the behaviour of a system of N identical pairs of fermions within the Hubbard model. I will show that with certain types of interaction, the ground state of this system will be reduced to an N-partite bosonic Fock state.
    Chair: Prof. Ryszard Tanaś
    Seminar language: English
  71. /411/
    Date: Wednesday 2018.11.28
    Speaker: Dr hab. Paweł Kurzyński
    Affiliation: Quantum Electronics Division, Physics Faculty, AMU
    Title: Evolution of negative probability distributions
    Abstract: There is an intriguing idea that quantum theory would be recovered if standard probabilities were replaced by negative probabilities and some events were deemed unobservable. However, such approach would be able to recover only one half of quantum theory - state description and measurement. The other half of the theory describes how states change in time. In this presentation I will discuss which evolutions of negative probability distributions are allowed. It is known that the evolution of standard probability distributions is determined by stochastic matrices, which generate either simple reversible permutations, or fundamentally irreversible dynamics. On the other hand, the evolution of negative probability distributions can be described by pseudo-stochastic matrices, i.e., matrices whose entries are given by negative probabilities. These matrices give rise to a much richer dynamics in which there are nontrivial reversible transformations.
    Chair: Prof. Ryszard Tanaś
    Seminar language: English
  72. /410/
    Date: Wednesday 2018.11.28
    Speaker: Prof. Andrzej Grudka
    Affiliation: Quantum Electronics Division, Physics Faculty, AMU
    Title: Time travel and the Second Law of Thermodynamics
    Abstract: One of the most surprising predictions of general relativity is possibility of time travel into one’s past. These so called closed timelike curves lead to the grandfather paradox. However Deutsch and also Bennett and Schumacher proposed quantum models which avoid this paradox. In this talk we show what are implications of these models to the Second Law of Thermodynamics.
    Chair: Prof. Ryszard Tanaś
    Seminar language: English
  73. /409/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Vojtěch Trávníček
    Affiliation: Joint Laboratory of Optics of Palacký University, Olomouc, Czech Republic
    Title: Experimental measurement of nonlinear entanglement witness by hyper-entangling two-qubit states
    Abstract: We demonstrate that non–linear entanglement witnesses can be made particularly useful for en- tanglement detection in hyper–entangled or multilevel states. We test this idea experimentally on the platform of linear optics using a hyper–entangled state of two photons. Instead of several simultaneous copies of two-photon entangled states, one can directly measure the witness on single copy of a hyper–entangled state. Our results indicate that hyper–entanglement can be used for quick entanglement detection and it provides a practical testbed for experiments with non–linear entanglement witnesses.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  74. /408/
    Date: Wednesday 2018.11.28
    Speaker: M.Sc. Kateřina Jiráková (Olomouc)
    Title: Experimental counterfeiting of quantum money
    Authors: Kateřina Jiráková (1*), Karol Bartkiewicz (2,1), Antonín Černoch (3), and Karel Lemr (1)
    (1) RCPTM, Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Olomouc, Czech Republic
    (2) Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
    (3) Institute of Physics of Academy of Sciences of the Czech Republic, Joint Laboratory of Optics of PU and IP AS CR, Olomouc, Czech Republic
    (*) Presently on leave at Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
    Abstract: The concept of quantum money has been originally suggested by S. Wiesner in the 1970s. Its main advantage is that every attempt to copy quantum banknotes leaves the quantum states changed providing a mark on money counterfeits. According to the no-cloning theorem the quantum states cannot be in general perfectly cloned (copied). However, an imperfect cloning is still possible. We present a version of an eavesdropping attack on the protocol proposed by Bozzio et al. (2018). The aim of our research is to demonstrate that cloning implemented even rarely enough that it is indistinguishable from noise is fully sufficient to acquire useful information to counterfeit quantum banknotes. We exploit the fact that completely random encoding of quantum banknotes is computationally impractical and that the bank needs to select a non-random but secret encoding algorithm. Data analysis or machine learning allow the attacker to discover bank’s secret and thus predict future banknotes merely on the basis of partial information gained by cloning of previous banknotes.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  75. /407/
    Date: Wednesday 2018.11.28
    Speaker: Dr hab. Karel Lemr (invited speaker)
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Diagnosing quantum relays by means of collective entanglement witnesses
    Abstract: The talk discusses the possibility to use collective entanglement witnesses, namely the collectibility, in quantum relay diagnostics. Theoretical concept as well as an experimental implementation shall be presented. The talk promotes benefits of this idea by comparing its experimental requirements with previously used methods.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  76. /406/
    Date: Wednesday 2018.11.28
    Speaker: Prof. Wiesław Leoński (keynote speaker)
    Affiliation: Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Zielona Góra, Poland
    Title: Quantum steering in a system of three qubits – some remarks and findings
    Abstract: We discuss a system of three qubits and concentrate on the quantum steering effect appearing in such a system. In particular, we discuss the relations of the steering with the other form of quantum correlations, the quantum entanglement [1,2]. Additionally, we present how the interesting us effects can appear in the three-mode triangle Bose–Hubbard system [3].
    [1] J. K. Kalaga, W. Leoński, Quant. Inf. Process. (2017) 16:175
    [2] J. K. Kalaga, W. Leoński, J. Perina Jr., Phys. Rev. A (2018) 97:042110
    [3] J. K. Kalaga, W. Leoński, R. Szczęśniak Quant. Inf. Process. (2017) 16:265
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  77. /405/
    Date: Wednesday 2018.11.28
    Speaker: Prof. Ryszard Tanaś (keynote speaker)
    Affiliation: Nonlinear Optics Division, Physics Faculty, Adam Mickiewicz University, Poznań, Poland
    Title: Violation of monogamy relations for negativity in a three-atom system
    Abstract: Quantum correlations in multi-qubit systems are subject of intensive studies because of their crucial role in quantum information processing. Probably the most popular measure of correlations is entanglement, but there are other measures that have been introduced and studied, such as quantum discord, geometric quantum discord, measurement induced disturbance and others. The simplest bipartite system in which the correlations can be studied is a system of two qubits, or two two-level atoms. In case of two-level atoms interacting with the reservoir of electromagnetic field modes in the vacuum, the evolution of the system can be described by the well known Lehmberg-Agarwal master equations. The collective evolution of the two-atom system depends on two collective parameters: collective damping 12 and dipole-dipole interaction γ12, which both depend on the interatomic distance. Such a system is a good testing ground for studying evolution of quantum correlations. We study a more complex system of three-atoms embedded in a common vacuum. Such a system is more difficult to describe because, for mixed states, we deal with 8×8 matrix which leads to 63 equations, and, what is even worse, there are no formulas to calculate concurrence, even if we know all the matrix elements. Fortunately, it is possible to calculate negativity, which is another measure of entanglement. Concurrence and negativity give the same values for pure states, but are different for mixed states. So, we use negativity as a measure of entanglement in a three-atom system. Master equation for the density matrix is solved, and we find evolution of the negativity in a three-atom system. The evolution depends on the collective parameters γij and Ωij. We test, in particular, the so called monogamy relations for negativity, for chosen initial states of the system. It is shown that for some states monogamy relations are violated.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  78. /404/
    Date: Monday 2018.11.26 at 13:00
    Speaker: Prof. Oleksandr V. Dobrovolskiy
    Affiliation: Physics Department, V. N. Karazin Kharkiv National University, Ukraine, and
    Physikalisches Institut, Goethe University Frankfurt am Main, Germany
    Title: Spin-wave phase inverter upon a single nanodefect
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  79. /403/
    Date: Wednesday 2018.11.14 at 13:00
    Speaker: M.Sc. Karol Gietka
    Affiliation: Katedra Optyki Kwantowej i Fizyki Atomowej, Instytut Fizyki Teoretycznej Uniwersytetu Warszawskiego
    Title: Quantum metrology beyond entanglement and measurement
    Abstract: During the seminar, I will give a short introduction to quantum metrology, which, generally speaking, aims at enhancing the sensitivity of measurement beyond the classical limit of precision. One of the most exciting aspects of quantum metrology is the possibility to harness entangled states of many-body quantum systems. On the example of a two-mode Bose-Einstein condensate, I will show how to generate such states and use them subsequently in the process of estimating an unknown parameter. I will explain why entangled states can enhance the sensitivity of measurement and why the use of them is currently restricted to proof-of-principle experiments. To overcome this limitation, I will show an alternative way (without entanglement) of enhancing the sensitivity by exploiting features of an exotic state of matter known as supersolid. Finally, I will show how one of the central theoretical tools in quantum metrology, quantum Fisher information, can be used to study quantum chaos.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  80. /402/
    Data: środa 2018.11.7
    Prelegent: Dr Kacper Drużbicki
    Afiliacja: Zakład Radiospektroskopii, Wydział Fizyki UAM
    Tytuł: Obliczenia periodyczne w formalizmie DFT jako narzędzie wspomagające badania struktury i własności dynamicznych kryształów molekularnych (seminarium habilitacyjne)
    Streszczenie: Współczesna krystalografia stanowi podstawowe narzędzie badania struktury kryształów molekularnych. Statyczny obraz struktury średniej kryształu, definiowanej przez uporządkowanie dalekiego zasięgu, ma bez wątpienia znaczenie fundamentalne, jest on jednak obrazem niepełnym. Spojrzenie na kryształy molekularne z alternatywnej perspektywy, tj. lokalnego otoczenia molekuły, pozwala uzupełnić naszą wiedzę na temat struktury i dynamiki sieci krystalicznej oraz rządzących nią oddziaływań. W tym kontekście, metody spektroskopii ciała stałego stanowią nieodzowne narzędzie badawcze, gdzie spektroskopia jądrowego rezonansu magnetycznego, NMR, może być uznana za metodę wiodąca prym. Rozwój spektroskopii NMR doprowadził do zaproponowania koncepcji krystalografii NMR, uznanej powszechnie jako pełnowartościową metodę badań strukturalnych. W referacie przedstawiona zostanie analiza możliwości wykorzystania wspieranych-obliczeniowo metod komplementarnych do NMR w badaniach kryształów molekularnych wykazujących różny stopień nieporządku. Bazując głównie na metodach spektroskopii neutronowej, przedstawione zostaną przykłady badań układów o znaczeniu zarówno poznawczym (kryształy molekularne z wiązaniem wodorowym) jak i aplikacyjnym (substancje farmaceutyczne oraz perowskitowy materiał fotowoltaiczny).
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  81. /401/
    Date: Friday 2018.10.12
    Speaker: prof. Mitsuteru Inuoe
    Affiliation: Toyohashi University of Technology, Japan; 2018 Distinguished Lecturer of IEEE Magnetics
    Title: Magnetic Phase Interference in Artificial Magnetic Lattices: Functions and Applications to Optical, High-Frequency, and Spin Wave Devices
    Abstract: The introduction of artificial magnetic structures into magnetic materials can induce novel electromagnetic and spin-wave behavior. Nano- and submicrometer-scale artificial magnetic lattices (AMLs) can control optical (electromagnetic) waves in magnetophotonic crystals [1], volumetric magnetic holograms [2], and labyrinthian magnetic domain structures [3], and can affect spin waves in magnonic crystals [4]. In this talk, the fundamental properties of such AMLs, mainly in magnetic garnet films and alloy thin films, are discussed, followed by demonstrations of their applications in optical and spin-wave micro-devices driven by magnetic phase interference: volumetric magneto-optic (MO) hologram memories [2] and three-dimensional MO holographic displays [5] with magnetophotonic crystals; high-speed MO Q-switch micro-chip lasers with iron-garnet films with labyrinthian magnetic domain structures [3]; and highly sensitive magnetic sensors and spin-wave logic circuits with magnonic crystals [6]. Prospective future spin-wave devices with AMLs will be discussed in the context of the new paradigm of magnonics (electron non-transport electronics), where spin waves play an important role as the information carrier.

    [1] T. Goto et al., “Magnetophotonic crystal comprising electro-optical layer for controlling helicity of light,” J. Appl. Phys., vol. 111, 07A913, 2012.
    [2] Y. Nakamura et al., “Error-free reconstruction of magnetic hologram via improvement of recording conditions in collinear optical system,” Optics Exp., vol. 25, pp. 15349-15357, 2017.
    [3] R. Morimoto et al., “Magnetic domains driving a Q-switched laser,” Sci. Rep., vol. 6, 38679, 2016.
    [4] N. Kanazawa et al., “Metal thickness dependence on spin wave propagation in magnonic crystal using yttrium iron garnet,” J. Appl. Phys., vol. 117, 17E510, 2015.
    [5] K. Nakamura et al., “Improvement of diffraction efficiency of three-dimensional magneto-optic spatial light modulator with magnetophotonic crystal,” Appl. Phys. Lett., vol. 108, 022404, 2016.
    Biography: Mitsuteru Inoue received the B.S. degree in information engineering and the M.S. and DrEng. degrees in electrical and electronic engineering in 1981, 1983, and 1989 from Toyohashi University of Technology (TUT), Japan. He was an associate professor at TUT from 1993 to 1996, and with the Research Institute of Electrical Communication, Tohoku University, from 1997 to 1999. From 2001 to 2013 he served as professor in the Department of Electrical and Electronic Engineering, TUT. Since 2014 he is jointly serving as professor of the Graduate School of TUT and as an executive trustee and vice president of TUT. He was a visiting professor at Stanford University in 2003 and at Moscow State University in 2004.
    His research interests include spin-coupled wave propagation phenomena in amorphous alloy and magnetic garnet thin films, including phase modulation of magneto-surface-acoustic-waves, control and phase modulation of optical waves, and control of high-frequency magnetostatic and spin waves, together with their applications in magneto-optical (MO) spatial light modulators, three-dimensional MO displays, non-destructive MO imaging, magnetic hologram recording, and spin-wave logic circuits.
    Prof. Inoue has served as the director of Magnetics Society of Japan from 2013 to 2015 and as the general chair of the Magnetics and Optics Research International Symposium (MORIS, 2015 and 2018). He is currently the chair of the 147th Committee on Amorphous and Nano-Crystalline Materials of the University-Industry Cooperative Research Committees, Japan Society for the Promotion of Science (JSPS). [copied from] 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  82. /400/
    Data: środa 2018.10.03
    Prelegent: Dr Mateusz Kempiński
    Afiliacja: Zakład Fizyki Dielektryków, Wydział Fizyki UAM
    Tytuł: Zjawiska transportu i lokalizacji nośników ładunku w układach grafenowych i grafeno-podobnych (Seminarium habilitacyjne)
    Streszczenie: Opisywane osiągnięcie naukowe dotyczy badań nad transportem i lokalizacją nośników ładunku i spinu w układach, których podstawową jednostką strukturalną jest płaszczyzna grafenowa. Badano dwie klasy materiałów: tlenki grafenu (o różnej zawartości tlenu w strukturze) oraz aktywowane włókna węglowe (o różnej porowatości). W prezentowanych badaniach użyte zostały trzy techniki badawcze: elektronowy rezonans paramagnetyczny, spektroskopia impedancyjna oraz stałoprądowy pomiar oporu elektrycznego, wsparte obrazowaniem mikroskopii elektronowej i analizą struktury chemicznej za pomocą spektroskopii fotoelektronów. Pomiary przeprowadzano w szerokim zakresie temperatur i w ściśle kontrolowanej atmosferze. Umożliwiło to zaobserwowanie zmian zachodzących w zachowaniu nośników ładunku w układach grafenowych w zależności od parametrów strukturalnych i fizykochemicznych oraz pod wpływem adsorpcji różnego rodzaju molekuł i zewnętrznego pola elektrycznego. Przedstawione wyniki pozwalają na wskazanie możliwości kontroli zachowania nośników ładunku w badanych materiałach, pod kątem zwiększenia ich przydatności w różnych zastosowaniach.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  83. /399/
    Date: Tuesday 2018.09.26
    Speaker: Dr Ievgen I. Arkhipov
    Affiliation: Joint Laboratory of Optics of Palacky University and Institute of Physics of CAS, Olomouc, Czech Republic
    Title: Complete characterization of nonclassicality of Gaussian states of light by means of intensity moments
    Abstract: Nonclassicality of light plays a crucial role in the field of quantum optics. The discovery of the nonclassical properties of light has led to the establishment of new branches of quantum physics, e.g., quantum information theory. One of the most known form of the nonclassicality of light is the entanglement, where different modes of quantum fields exhibit quantum correlations which have no analogue in the classical optics. Though a lot of progress has been made in the theory of the nonclassicality of the Gaussian states, still, the problem, how one can directly certify the nonclassicality of the Gaussian states in the experiment with the least available sources, has not been solved yet. During the seminar, I will present a new experimental method for complete identification of nonclassicality of Gaussian states of light in the whole phase space. The proposed method relies on nonclassicality witnesses written in terms of measured integrated intensity moments up to the second order, provided that appropriate local coherent displacements are applied to the state under consideration.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  84. /398/
    Data: środa 2018.09.19, godz. 13:00
    Prelegent: Dr hab. Marcin Ziółek
    Afiliacja: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
    Tytuł: Korelacje parametrów fotoogniw z wynikami czasowo-rozdzielczych badań laserowych (Seminarium profesorskie)
    Streszczenie: Impulsowa spektroskopia laserowa pracująca w zakresie femtosekund, pikosekund i nanosekund staje się ważnym i coraz bardziej popularnym narzędziem badań podstawowych, umożliwiającym obserwacje najszybszych procesów zachodzących w przyrodzie. Za pomocą takiej spektroskopii możemy także poznać mechanizmy i dynamikę procesów transportu ładunków w fotoogniwach. Czy jednak badania z użyciem femtosekundowych impulsów laserowych mogą dzięki temu zostać użyte do bardziej praktycznych celów i pomóc w uzyskiwaniu lepszej sprawności ogniw słonecznych? Od kilku lat rozwijamy w naszej grupie badawczej czasowo-rozdzielcze absorpcyjne i emisyjne techniki laserowe stosowane do pomiarów fotoogniw barwnikowych (dye-sensitized solar cells) oraz fotoogniw perowskitowych. Specjalizujemy się w badaniu gotowych ogniw, które konstruujemy i dla których wykonujemy podstawowe pomiary fotowoltaiczne. Takie funkcjonale próbki są przedmiotem spektroskopowych badań laserowych, których głównym celem jest zaobserwowanie korelacji między zmierzonymi parametrami ogniw słonecznych a wynikami badań w krótkich czasach.
    Prowadzący: Dr hab. Krzysztof Gibasiewicz
    Seminar language: English
  85. /397/
    Date: Wednesday 2018.09.5
    Speaker: Dr Karol Bartkiewicz
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
    Title: Nonlinear temporal and spatial properties of quantum states: sequential and interferometric measurement methods in optics (Seminarium habilitacyjne)
    Abstract: Quantum information processing is an interdisciplinary field of research where physics meets information science and engineering. Its potential applications range from securing communications to solving computational tasks that have been infeasible on computers that relied on classical physics. These applications exploit the quantum features of a given quantum state through specifically designed hardware, e.g., quantum entanglement, fidelity, and temporal steering. Full quantum tomography is frequently conducted to characterise some of these features, which becomes prohibitively time consuming, especially in large systems. In this talk, I discuss alternatives to characterising quantum systems based on sequential and interferometric methods as well as experimental challenges related to their implementation.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  86. /396/
    Date: Wednesday 2018.08.8
    Speaker: Doc. Karel Lemr
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Multiphoton experiments in Olomouc
    Abstract: The talk will present the current state of the multiphoton quantum laboratory in Olomouc. I shall summarize recent experiments with three and four photons as quantum information carriers. Specifically, I will discuss our experiments on collective entanglement witnesses, quantum router and controlled quantum teleportation.
    Chair: Dr Karol Bartkiewicz
    Seminar language: English
  87. /395/
    Date: Monday 2018.07.23
    Speaker: M.Sc. Jessica Taylor Flach
    Affiliation: Department of Chemistry, University of Wisconsin–Madison, USA
    Title: Two-dimensional white-light spectroscopy and its applications for understanding carbon nanotube and perovskite photophysics
    Abstract: This talk will give a general overview of the techniques involved in using two-dimensional electronic spectroscopy (2D-ES) and illustrate how 2D-ES can be used to study energy and charge transfer processes in materials of interest for next generation photovoltaics. The first part of this talk will focus on understanding the photophysics of carbon nanotube thin films and devices. Using our two-dimensional white-light (2D-WL) spectrometer we are able to explore exciton diffusion and hopping dynamics in order to better inform carbon nanotube device design. In the second part of this talk I will discuss our newer, faster version of 2D-WL spectroscopy using a pulse shaper and present an initial report on perovskite photophysics.
    Chair: Prof. UAM Marcin Ziółek
    Seminar language: English
  88. /394/
    Date: Wednesday 2018.07.11
    Speaker: Dr Jorge Augusto Otálora Arias
    Affiliation: Institute for Metallic Materials Leibniz Institute for Solid State and Material Research, Dresden, Germany
    Title: Towards a three dimensional curvilinear magnonic device
    Abstract: The research field called Magnonics emerged with the paradigm of harnessing spin-waves (SWs) as the elemental carrier of information. With up to terahertz (THz) oscillation frequencies with nanometric wavelengths and over macroscopic propagation distances without electron charges being displaced, harnessing magnons paves the way toward applications with minimum joule heating effect, therefore with unprecedentedly low power consumption (energy- friendly environmental devices), reconfigurable functionality, faster operation and further miniaturization. The wavelike properties of SWs as phase and amplitude provides additional degrees of freedom in data processing and sensing, which lead for instance, to novel prototype building blocks of SW-based logic [1] and smart device for very efficient SW propagation channels [2]. The kernel of such applications generally consists of the so-called magnonic waveguides (MGs) and magnonic crystals (MCs), which are meta-materials characterized by their unprecedented on-demand reprogrammable functionality. Whether MGs or MCs, three aspects are generally assessed at the moment of studying SWs properties for fundamental physics and magnonic applications: (i) High efficiency in transmitting SWs power along magnetic tracks with minimum energy consumption, sub-micrometer wave length encoding (< 1 µm), large group velocity limits ( > 1000 m/s), large decay length ( > 6 µm) and small frequency linewidth ( < 100 MHz); (ii) large and tunable nonreciprocities in the dispersion relation, amplitude, power absorption, frequency linewidth and decay length of SWs, at sub-micrometer wavelengths, above GHz frequency range, and minimized energy expenditure. This feature is particularly advantageous in analog and digital operation based in SW logic devices, since non-reciprocity provides the condition for the unidirectional propagation of SW packages (avoiding the formation of standing SWs), which is strategic for enhancing the input/output information transfer encoded in the phase, frequency and amplitude of SWs; and (iii) efficient interface for input/output signals conversion between magnons and other types of information carries at high resolution of SW phase and frequency, and over a broad range of frequency coverage. Accordingly, it can be suggested that the ideal magnonic layout is that one which allows the versatility of enclosing the aforementioned three aspects in one single device; hence the potential of SWs as information carriers can be fully exploited. According to literature, these three aspects have been mainly studied in planar two-dimensional (2D) thin films, nevertheless, there is not yet a clear example wherein all of them can be achieved in only one single magnonic layout at once. We think that a promising route would consist in curving the 2D template into a curvilinear 3D-dimesional geometry, which simultaneously bring novelty to Magnonics because the intrinsic curvature-induced magneto-chiral effects in SWs.[3-5] This talk will be addressed in this direction.
    [1] Wang et al., Sci. Adv. 4, e1701517 (2018)
    [2] Wagner et al., Nat. Nanotech. (2016)
    [3] Otálora et al., Phys. Rev. Lett. 117, 227203 (2016)
    [4] Otálora et al., Phys. Rev. B. 95, 184415 (2017)
    [5] Otálora et al., Phys. Rev. B. 98, 014403 (2018)
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  89. /393/
    Date: Tuesday 2018.07.10
    Speaker: M.Sc. Edgar Aguilar
    Affiliation: National Quantum Information Centre, University of Gdańsk, Sopot, Poland
    Title: Certifying an Irreducible 1024-Dimensional Photonic State Using Refined Dimension Witnesses
    Abstract: We report on a new class of dimension witnesses, based on quantum random access codes, which are a function of the recorded statistics and that have different bounds for all possible decompositions of a high-dimensional physical system. Thus, it certifies the dimension of the system and has the new distinct feature of identifying whether the high-dimensional system is decomposable in terms of lower dimensional subsystems. To demonstrate the practicability of this technique, we used it to experimentally certify the generation of an irreducible 1024-dimensional photonic quantum state. Therefore, certifying that the state is not multipartite or encoded using noncoupled different degrees of freedom of a single photon. Our protocol should find applications in a broad class of modern quantum information experiments addressing the generation of high-dimensional quantum systems, where quantum tomography may become intractable [1].

    [1] Edgar A. Aguilar, Máté Farkas, Daniel Martínez, Matías Alvarado, Jaime Carine, Guilherme B. Xavier, Johanna F. Barra, Gustavo Canas, Marcin Pawłowski, and Gustavo Lima, Phys. Rev. Lett. 120, 230503 (2018).
    Chair: Dr hab. Paweł Kurzyński
    Seminar language: English
  90. /392/
    Data: piątek 2018.07.6
    Prelegent: Dr hab. Jolanta Natalia Latosińska
    Afiliacja: Wydział Fizyki UAM
    Tytuł: „Całość to znacznie więcej niż suma części” – niezależnie od skali (Seminarium profesorskie)
    Streszczenie: Synergia (z gr. “συν” oznaczające “razem”, oraz “ϵργια” – dzieło, działanie) w kontekście badań naukowych oznacza podejście całościowe – kompleksowe. Od początku kariery naukowej zdecydowałam się na interdyscyplinarny charakter swoich badań i podążałam w tym kierunku konsekwentnie, pomimo wielu przeciwności. Obecnie badania interdyscyplinarne stanowią swego rodzaju standard, ale w latach 90-tych takie podejście łączenia ze sobą różnych dziedzin było nawet nie do pomyślenia. Jednakże ja upatrywałam w nim nie tylko szanse na poszerzanie perspektyw badawczych, ale i kryjący się za tym ogromny potencjał. Z upływem czasu tematyka moich interdyscyplinarnych prac naukowych stopniowo ewoluowała w kierunku poszerzonej interdyscyplinarności (multidyscyplinarności), łącząc fizykę, chemię, informatykę, farmację, biofizykę, a w ostatnich latach również matematykę, meteorologię, klimatologię, astronomię oraz ochronę środowiska.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  91. /391/
    Date: Wednesday 2018.07.4
    Speaker: Dr Zbigniew Rozynek
    Affiliation: Institute of Acoustics, Faculty of Physics, UAM
    Title: Particle assembly and droplet manipulation by electric fields (Seminarium habilitacyjne)
    Abstract: Droplets covered by micro- and nanoparticles have recently received considerable research interest, as they are promising for various practical applications, such as in food technology, the oil industry, biofuel processing, and improving pharmaceutical products. Moreover, such droplets possess characteristics that make them useful as experimental model systems for studying, for example, particle effects on interfacial tension, particle crystal growth and ordering or particle-layer buckling on curved interfaces, particle assembly and rearrangement on droplets’ surfaces, and particle detachment from droplets. Particle-covered droplets can additionally be employed for fabricating porous structures, granular or colloidal capsules of different mechanical properties, morphologies, or shapes, and adaptive structures. In this context, broadening one’s knowledge of particle-covered droplet stability, deformation, and surface-particle manipulation is essential to further developing the above-mentioned research areas. The deformation of droplets can be induced and investigated using various experimental tools, including atomic force microscopes, microfluidic devices, or mechanical shearing. For manipulating the surface or bulk particles, many physical or chemical approaches exist, such as pH-controlled particle assembly, acoustic wave–induced bulk and surface particle convection, magnetic field–directed particle assembly, and electric field–assisted particle arrangements. In this seminar I will demonstrate how we utilized various electric field phenomena to study the behaviour of particle-covered droplets subjected to electric fields, including steady-state deformation and transient deformation of such droplets, as well as the mechanics and rheological properties of particle shells formed on droplets. I will also show that electric fields can be used for manipulating particles in the bulk and at the surface of the droplet by exerting forces that were acting on them either directly, e.g. through particle motion via dipolar forces, or indirectly, e.g. by particle convection through electric field–induced liquid flows.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  92. /390/
    Date: Tuesday 2018.07.03
    Speaker: Prof. Richard J. Spontak
    Affiliation: Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh NC 27695
    Title: Photodynamic Polymers as Comprehensive Anti-Infective Materials: Staying Ahead of a Growing Global Threat
    Abstract: Adherence of pathogens such as bacteria and viruses on various surfaces routinely leads to subsequent transmission to new hosts, significantly promoting the proliferation of potentially harmful organisms. This sequence is particularly worrisome in the case of antibiotic-resistant pathogens, which are becoming a global threat to human health. According to the Centers for Disease Control and Prevention, 1 out of every 20 hospital patients is affected by nosocomial infections, subsequently resulting in 100,000 deaths annually in the United States alone. Out of these, about 23,000 deaths are attributed to drug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (S. aureus) or vancomycin-resistant Enterococcus faecium (E. faecium). Strains referred to as "nightmare bacteria" with highly elevated resistance to last-resort antibiotics have been reported all around the world in 2017. While silver, copper, zinc oxide or titanium dioxide have been used as surfaces or introduced as nanoparticles into a broad range of substrates to serve as antimicrobial agents and eradicate a wide range of pathogens, they all suffer from eventual reservoir depletion, and they tend to be pathogen- or condition-specific. Moreover, if not covalently bound or tightly embedded, these nanoparticles can leach into the environment and introduce additional health concerns. In this study, we discuss a photodynamic polymer composed of an olefinic thermoplastic elastomer modified with zinc tetra(4-N-methylpyridyl)porphine (ZnTMPyP4+), a photoactive antimicrobial, and demonstrate that this combination is remarkably effective at inactivating 5 bacterial strains, including S. aureus and Escheria coli (E. coli) often associated with food poisoning, and 2 different viruses, including Human adenovirus-5, upon exposure to non-coherent light at an intensity of 65-80 mW/cm2 for 60 min. By achieving antibacterial and antiviral efficacies of at least 99.89% and 99.95%, respectively, this methodology based on the light-induced creation of singlet oxygen constitutes a non-specific and highly successful route by which to eliminate harmful pathogens by simple exposure to visible light and oxygen.
    Chair: Prof. Michał Banaszak
    Seminar language: English
  93. /389/
    Date: Wednesday 2018.06.27
    Speaker: Dr-Ing. Wolfgang Jaschinski
    Affiliation: Leibniz Research Centre for Working Environment and Human Factors, Technische Universität Dortmund
    Title: Physical dimensions follow physiological functions: Ergonomics at the computer workstation.
    Abstract: Using computers means work for muscular systems, e.g. the intra-ocular muscle of the focussing system in the eyes, the extra-ocular muscles for moving the eyes, the muscles of the neck and the back. These physiological systems have properties that have developed during evolution in natural environments. For comfortable computer work, these individual physiological functions should be considered when arranging and designing the computer workstation for the individual user. Optometry provides appropriate eye glasses for clear vision.
    [1] Jaschinski W (2017) Individual Objective and Subjective Fixation Disparity in Near Vision. PLoS ONE 12(1).
    [2] Schroth, V.; Joos, R.; Jaschinski, W.: Effects of prism eyeglasses on objective and subjective fixation disparity. PLoS ONE 10: e0138871 (29 pp.) (2015)
    [3] Weidling P, Jaschinski W: The vertical monitor position for presbyopic computer users with progressive lenses: how to reach clear vision and comfortable head posture. Ergonomics 58: 1819-1829 (2015)
    [4] Jaschinski W, König M, Mekontso TM, Ohlendorf A, Welscher M: Comparison of progressive addition lenses for general purpose and for computer vision: an office field study. Clin Exp Optom 98: 234-243 (2015)
    [5] König M, Haensel C, Jaschinski W: How to place the computer monitor: measurements of vertical zones of clear vision with presbyopic corrections. Clin Exp Optom 98: 244-253 (2015)
    Chair: Dr Alicja Brenk-Krakowska
    Seminar language: English
  94. /388/
    Date: Friday 2018.06.22
    Speaker: Dr Ravindra Chhajlany
    Affiliation: Solid State Theory Division, Physics Faculty, AMU
    Title: Field-controlled quantum matter: exploration of long-range order in reduced dimensions (Kwantowa materia kontrolowana światłem: dalekozasięgowe uporządkowania w zredukowanych wymiarach) - Seminarium habilitacyjne
    Abstract: The forms of so-called “quantum matter” - where quantum effects are crucially manifested at the macroscopic scale - range from phases of “traditional” strongly correlated many body systems to exotic topological systems. Research on two parallel wide classes of systems are providing access and understanding to various aspects of many body physics - (i) so called quantum simulators of matter (“idealized materials”), and of course (ii) various real materials, controlled in novel ways. In particular, quantum simulators in controlled environments based on platforms of ultracold particles trapped in optical lattices, ion traps, nano-photonic systems can be engineered to access often extreme parameter regimes rarely accessible before in real materials, using control via light or magnetic fields. Similarly, advances in ultra-fast spectroscopy are facilitating the manipulation of real materials at a microscopic level using light instead of the more traditional control of pressure, temperature etc. These new ways of controlling and manipulating matter pose theoretical challenges. In this seminar, I will summarize some results of research that I have been part of in this exciting field that will constitute my Habilitation dissertation - all of which concern the description of properties and control of long range ordered phases in d=1 or 2 dimensional systems . In particular, I will talk about: (i) engineering extreme correlated hopping for ultra-cold atoms and associated physical properties (ii) non-trivial gauge field effects in an exemplary one-dimensional system (iii) effects of gauge fields in a spinor boson gas (iv) proximity effects in an engineered bilayer system and (v) control of orbital order in a paradigmatic manganite.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  95. /387/
    Data: środa 2018.06.20
    Prelegent: Dr n. med. Krzysztof Michalak
    Afiliacja: Pracownia Fizyki Widzenia i Optometrii, Wydział Fizyki UAM
    Tytuł: Wyznaczanie złożoności wysokowymiarowych sygnałów nieliniowych (Seminarium habilitacyjne)
    Streszczenie: Sygnały chaotyczne to sygnały opisane przez deterministyczne układy równań różniczkowych, których rozwiązaniem jest nieregularny przebieg zmiennych w czasie. Jedną z miar ukrytej, częściowej regularności jest Wymiar Korelacyjny (d, Correlation Dimension). Dostępne w literaturze algorytmy wyznaczania tego parametru dają jednak błędne wyniki w przypadku sygnałów wysoko wymiarowych, czyli o złożoności przekraczającej d=5. Prezentacja przedstawia wyniki wielu symulacji numerycznych i analiz wyjaśniających przyczyny błędów estymacji dla sygnałów wysoko wymiarowych oraz poprawne sposoby wyznaczania tego parametru. Analiza skupiona była zarówno na poprawieniu dokładności wyznaczania d, oszacowaniu dokładności tej estymacji, jak i na przyspieszeniu obliczeń, które w przypadku sygnałów wysoko wymiarowych są bardzo czasochłonne. Końcowym efektem pracy jest w dużej mierze nowy algorytm, który wyznacza d z dużą dokładnością w znacznie krótszym czasie i który zaimplementowany jest w zestawie funkcji Matlab udostępnionych do swobodnego wykorzystania. Metoda może mieć zastosowanie w wielu dziedzinach nauki, w których mamy do czynienia z układami chaotycznymi: w fizyce, chemii, biologii, ekonomii, meteorologii itp.
    Prowadzący: Prof. Adam Miranowicz
    Seminar language: Polish
  96. /386/
    Date: Thursday 2018.06.14
    Speaker: Prof. Jan Peřina Jr.
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Science of the Czech Republic, Olomouc, Czech Republic
    Title: Sub-Poissonian light
    Abstract: Different definitions of higher-order sub-Poissonian-like fields based on the moments of integrated intensity, photon number, integrated-intensity fluctuation, photon-number fluctuation and using the elements of photocount (photon-number) distributions will be introduced. Their mutual relations will be elucidated. Using the set of potentially sub-Poissonian fields obtained by post-selection from a twin beam based on photon-number-resolving detection their power to experimentally indicate non-classicality will be discussed. The generation of sub-Poissonian-like optical fields up to the fifth-order in intensity moments and up to the eleventh-order in the elements of photocount distribution will be mentioned.
    Chair: Prof. Adam Miranowicz
  97. /385/
    Date: Monday 2018.06.11
    Speaker: Dr Andrii Sotnikov
    Affiliation: Institute of Solid State Physics, TU Wien, Vienna, Austria
    Title: Aspects of the Hubbard model and challenges for quantum computers
    Abstract: After 55 years since its formulation, the Hubbard model keeps many problems open till present days. We discuss main reasons for the difficulty to access particular regimes of this simple model even with modern computational possibilities. It will be shown that the Hubbard model is universal in the sense that it can describe large classes of materials and strongly-correlated many-body phases of interest, in particular, high-temperature superconductors and excitonic insulators. For these two cases, several recent experimental achievements and current level of theoretical description will be pointed out. With all problems in mind, a natural question arises: “Can universal quantum simulators or quantum computers help to gain further physical insights in the Hubbard model?” According to recent progress in these fields, we tend to answer “yes”, but there are still many challenges on the way.
    Chair: Dr Agnieszka Cichy
    Seminar language: English
  98. /384/
    Date: Wednesday 2018.05.30
    Speaker: Dr Piotr Biskupski
    Affiliation: IBM Systems - File Object Storage - Technical Leader, CEE, IBM Q Ambassador
    Title: The future is quantum - IBM Q experience
    Abstract: The rate of progress has been remarkable. Only a year and a half ago, we put the IBM Q experience prototype 5-qubit machine in the cloud, and made it available for the world to use, explore, and learn from. A year later, we added a second device with 16 qubits. Today, more than 60,000 users from more than 1,500 universities, 300 high schools, and 300 private institutions have registered for accounts on the IBM Q experience, and collectively run 1.7 million experiments. The members of the research community have also published more than 35 research papers using our platform as a testbed for ideas. This is only the beginning.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  99. /383/
    Data: poniedziałek 2018.05.28
    Prelegent: Dr Marta Targosz-Korecka
    Afiliacja: Zakład Fizyki Nanostruktur i Nanotechnologii, Wydział Fizyki, Astronomii i Informatyki Stosowanej, Uniwersytet Jagielloński
    Tytuł: Właściwości mechaniczne komórek w rozwoju oraz przebiegu chorób cywilizacyjnych - obraz na podstawie badań z wykorzystaniem mikroskopu sił atomowych (Seminarium habilitacyjne)
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  100. /382/
    Date: Monday 2018.05.21
    Speaker: Ph.D. Eng. Przemysław Głowacki
    Affiliation: Physikalisch-Technische Bundesanstalt, Braunschweig, Germany and Poznań University of Technology, Poznań, Poland
    Title: Laser spectroscopic characterization of the nuclear-clock isomer 229mTh
    Abstract: [PDF] 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  101. /381/
    Data: środa 2018.05.16
    Prelegent: Dr Piotr Kozłowski
    Afiliacja: Zakład Fizyki Komputerowej, Wydział Fizyki UAM
    Tytuł: Wyjaśnienie własności magnetycznych i elektronowych wybranych nanomagnetyków molekularnych na bazie jonów chromu i wanadu (Seminarium habilitacyjne)
    Streszczenie: [PDF] 
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  102. /380/
    Data: piątek 2018.05.11
    Prelegent: Dr Wojciech Dimitrow
    Afiliacja: Instytut Obserwatorium Astronomiczne, Wydział Fizyki UAM
    Tytuł: Układy wielokrotne gwiazd - powstawanie, obserwacje oraz modelowanie (Seminarium habilitacyjne)
    Streszczenie: Podczas prezentacji zostaną przedstawione wyniki obserwacji oraz modelowania układów wielokrotnych gwiazd zawierających parę zaćmieniową. W ramach wprowadzenia zostanie omówiony proces powstawania gwiazd w obłokach molekularnych. Przedstawione będą różne typy obiektów oraz interesujące wyniki obserwacyjne z ostatnich lat. Dynamika i stabilność takich układów oraz możliwość obecności planet jest kolejnym ważnym problemem. Tematyka powstawania gwiazd jest ściśle związana z badaniami układów wielokrotnych. Obserwacje dostarczają informacji które pozwalają zweryfikować współczesne teorie formowania się gwiazd. Przedstawione będą instrumenty badawcze dzięki którym zgromadzono dane spektroskopowe i fotometryczne niezbędne do modelowania pięciu wybranych układów wielokrotnych. Omówione zostaną podstawowe zastosowane metody - pomiarów prędkości radialnych (efekt Dopplera) oraz modelowania par zaćmieniowych. Dla pięciu badanych układów udało się odkryć nowe składniki spektroskopowe, wyjaśnić hierarchie układów oraz otrzymać parametry orbitalne, takie jak okresy, rozmiary, mimośrody oraz nachylenia. Ponadto wyznaczono masy, promienie, temperatury, kształt oraz skład chemiczny składników par zaćmieniowych. Na podstawie tych wyników można określić status ewolucyjny badanego obiektu oraz wyznaczyć jego odległość.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  103. /379/
    Data: środa 2018.05.09
    Prelegent: Prof. Jan Barciszewski
    Afiliacja: Instytut Chemii Bioorganicznej Polskiej Akademii Nauk i Centrum Nanobiomedyczne UAM, Poznań
    Tytuł: Genetyka to za mało
    Streszczenie: Nauki biologiczne można podzielić na biochemię, genetykę, biologię molekularną i epigenetykę. Generalnie biologia molekularna analizuje znane produkty znanych genów, biochemia zajmuje się badaniami znanych produktów nieznanych genów a zadaniem genetyki jest analiza znanych genów nieznanych produktów. Poznanie sekwencji nukleotydowej ludzkiego genomu w 2003 roku było jednym z największych osiągnięć genetyki. Genom człowieka składa się z ponad 3 miliardów par zasad i zawiera ok. 21000 genów kodujących białka, co stanowi zaledwie 2% genomu. Liczba genów człowieka jest tylko o około 50 większa od liczby genów szympansa, natomiast bakteria Escherichia coli ma 4300 genów, drożdże piwne - 6300 genów, rzodkiewnik pospolity – 25000, a ryż – 50000. Dwoje niespokrewnionych ludzi wykazuje identyczność 99,9% sekwencji nukleotydowej DNA. W całej populacji ludzkiej różnice dotyczą tylko 0,3% sekwencji genomu. Pozostałe 98% genomu, choć nie koduje białek (są tam mobilne elementy genetyczne, pseudogeny czy introny) jest tak samo ważna dla funkcjonowania komórki. Część pseudogenów pozostaje transkrypcyjnie nieaktywna, ale z większości powstają RNA, które nie są przepisywane na białko, ale mogą regulować ekspresję genów. Każda komórka naszego organizmu zawiera ten sam genom (DNA), ale mimo tego komórki bardzo się od siebie różnią. W komórce istnieją mechanizmy powodujące zmiany epigenetyczne (epi: poza, ponad), które wpływają na ekspresję genów ale nie zmieniają sekwencji DNA. Jednym z mechanizmów epigenetycznych jest metylacja DNA, a drugi modyfikacja (metylacja, acetylacja) histonów. Modyfikacje epigenetyczne, są często efektem reakcji organizmu na zmieniające się warunki otoczenia oraz decydują o jego możliwościach adaptacyjnych. Poszukiwania epigenetyczne polegają na identyfikacji elementów chemicznych, które modyfikują genom, zarządzają komórkami, i zmieniają długoterminową ekspresję genów. Okazało się, że nie tylko substancje chemiczne ale również uwarunkowania społeczne mogą wpływać na jej zakres. Modyfikacje epigenetyczne mogą się pojawić w wieku dorosłym, młodzieńczym, a nawet in utero. W konsekwencji, określone wydarzenie z dzieciństwa może zmienić sposób, w jaki geny reagują w innej sytuacji w wieku dorosłym. Przechodząc na grunt medycyny, zauważono, że w procesie nowotworzenia następuje obniżenie globalnego poziomu metylacji DNA oraz podwyższenie metylacji promotorów genów supresorowych a także modyfikacje histonów, co prowadzi do zmian w ekspresji genów. Bazując na tych obserwacjach, podejmowane są próby terapeutycznego wykorzystania mechanizmów epigenetycznych ograniczając negatywny wpływ demetylacji DNA czy acetylacji histonów.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  104. /378/
    Data: środa 2018.04.25
    Prelegent: Prof. Halina Abramczyk
    Afiliacja: Institute of Applied Radiation Chemistry, Łódź University of Technology
    Tytuł: Obrazowanie ramanowskie, AFM i SNOM w onkologii.
    Prowadząca: Dr Małgorzata Paprzycka
    Seminar language: Polish
  105. /377/
    Date: Tuesday 2018.04.24
    Speaker: Dr Peter Alexander Bouvrie
    Affiliation: Centro Brasileiro de Pesquisas Físicas
    Title: Quantum information with ultracold interacting Fermi gases
    Abstract: Multiparticle entangled states, essential ingredients for modern quantum technologies, are routinely generated in experiments of atomic Bose-Einstein condensates (BECs). However, entanglement in ultracold interacting Fermi gases has not been exploited yet. Here, using a theory of composite bosons we show that many-particle entanglement between two fermionic ensembles localized in spatially separated modes can be generated by splitting an ultracold interacting Fermi gas in the (molecular) BEC regime. This entanglement relies on the fundamental fermion exchange symmetry of molecular constituents and might be used for implementing quantum information tasks such as Bell test of quantum nonlocality. We also predict that large ensembles, of the order of 105 fully entangled fermionic atoms, could be generated in current experiments of ultracold interacting Fermi gases.
    Chair: Dr hab. Paweł Kurzyński
    Seminar language: English
  106. /376/
    Data: środa 2018.04.18
    Prelegent: Dr Wojciech Grudziński
    Afiliacja: Zakład Biofizyki, Instytut Fizyki, Wydział Matematyki, Fizyki i Informatyki, Uniwersytet Marii Curie-Skłodowskiej w Lublinie
    Tytuł: Synergistyczny efekt zastosowania spektroskopii fluorescencyjnej i ramanowskiej polienów w badaniach oraz obrazowaniu struktur biologicznych (Seminarium habilitacyjne)
    Streszczenie: Polieny, włączając karotenoidy oraz antybiotyk amfoterycyna B, odgrywają różne, niezwykle ważne role biologiczne. W układach naturalnych ich funkcjonowanie opiera się głównie na modyfikacji fizycznych właściwości błon oraz protekcyjnym działaniu antyoksydacyjnym. Organizacja tych cząsteczek w błonach lipidowych związana jest ściśle z mechanizmami molekularnymi odpowiedzialnymi za funkcje jakie odgrywają one w organizmach żywych. Komplementarne zastosowanie spektroskopii Ramana i spektroskopii fluorescencyjnej w badaniach polienów pozwala na unikalną analizę oraz obrazowanie struktur biologicznych w mikroskali. Podejście opierające się na równoczesnym użyciu dwu technik mikroskopowych wykorzystane zostało, między innymi, do badań organizacji molekularnej, lokalizacji oraz orientacji karotenoidów, a także antybiotyku polienowego. Podczas wystąpienia zaprezentowane zostaną wyniki badań oraz analizy przeprowadzone dla polienów (luteiny, zeaksantyny, amfoterycyny B) wbudowywanych do modelowych błon lipidowych w postaci bardzo dużych, jednowarstwowych struktur liposomowych (GUV ang. Giant Unilamellar Vesicles) formowanych z lecytyny. Dane uzyskane z pomiarów fluorescencyjnych umożliwiły określenie lokalizacji cząsteczek, a także dały podstawę do stwierdzenia jaką formę organizacji molekularnej przyjmują analizowane związki. Szczegółowa analiza z wykorzystaniem oryginalnej metody pozwoliła precyzyjnie wyznaczyć orientację polienów względem osi normalnej do błony lipidowej. Spektroskopia ramanowska, poza lokalizacją polienów w strukturach lipidowych, umożliwiła uzyskanie informacji o formach stereoizomerycznych karotenoidów występujących w badanych układach, a także o ich rozmieszczeniu w obrębie analizowanego systemu. Przedstawione badania pozwalają, między innymi zrozumieć rolę jaką odgrywają luteina i zeaksantyna w plamce żółtej oka ludzkiego oraz jakie jest ich znaczenie w procesie nieodwracalnej utraty wzroku w wyniku starczego zwyrodnienia siatkówki (AMD, ang. Age-related Macular Degeneration). Dzięki uzyskanym wynikom zweryfikowano hipotezy dotyczące funkcji ochronnych pełnionych przez karotenoidy na poziomie molekularnym. Przeprowadzone badania antybiotyku polienowego amfoterycyny B pozwoliły zidentyfikować molekularne determinanty toksyczności tego leku dla pacjentów.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  107. /375/
    Date: Wednesday 2018.04.11 at 13:00
    Speaker: Dr Michał Karpiński
    Affiliation: Quantum Photonics Laboratory, University of Warsaw
    Title: Spectral shaping of single-photon pulses
    Abstract: The spectral-temporal degree of freedom of light has recently been recognized as a promising platform for encoding and transmission of quantum information. This requires the ability to modify the spectral and temporal profiles of single-photon light pulses. During the seminar I will talk about the methods of spectral modification of quantum light using electro-optic phase modulation. This method allows to change the time-spectral profile of the light pulse in a deterministic and, in principle, unitary way, i.e. without the use of filtering or amplification. In particular, I will present experimental results on efficient modification of the spectral bandwidth of single-photon pulses of light and discuss their significance in the context of the development of quantum networks.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  108. /374/
    Data: środa 2018.03.28
    Prelegent: Dr Beata Łuszczyńska
    Afiliacja: Katedra Fizyki Molekularnej, Wydział Chemiczny, Politechnika Łódzka
    Tytuł: Podstawy fizyczne procesu optymalizacji organicznych i hybrydowych fotodiod pracujących w zakresie bliskiej podczerwieni (Seminarium habilitacyjne)
    Streszczenie: Organiczne urządzenia optoelektroniczne - diody elektroluminescencyjne, ogniwa fotowoltaiczne oraz fotodiody - wykazują szereg niezwykłych właściwości, takich jak elastyczność, lekka waga czy też możliwość wytwarzania elementów o dużej powierzchni tanimi metodami drukarskimi, które są nieosiągalne dla elektroniki nieorganicznej. Mimo to, drukowana elektronika organiczna nie znalazła jeszcze szerokiego zastosowania, gdyż parametry pracy tak wytworzonych urządzeń nie spełniają wymagań użytkowników. Seminarium będzie poświęcone metodzie optymalizacji struktury organicznych i hybrydowych fotodetektorów, w celu uzyskania urządzeń wykazujących dobre cechy użytkowe. Metoda ta jest oparta na analizie zjawisk fizycznych wpływających na parametry pracy fotodiod takich jak: generacja ekscytonów i ich dysocjacja na swobodne nośniki ładunku, rekombinacja, pułapkowanie i ruchliwość nośników ładunku, oraz przepływ prądów ograniczonych ładunkiem przestrzennym. Taka analiza będzie przeprowadzona na przykładzie dwóch klas urządzeń: fotodetektorów hybrydowych, w których warstwę aktywną stanowiły układy organiczno-nieorganiczne oparte na mieszaninie polimeru z nieorganicznymi nanocząstkami, oraz fotodetektorów polimerowych wykorzystujących odpowiednio zaprojektowane kopolimery donorowo-akceptorowe, które dzięki wąskiej przerwie energetycznej są zdolne do absorpcji światła z zakresu bliskiej podczerwieni. Proces optymalizacji obejmował także dobór warstw blokujących niepożądany przepływ ładunku, których zastosowanie umożliwia uzyskanie zbalansowanego transportu elektronów i dziur oraz obniżenie prądów ciemnych co zwiększa czułość fotodiod. Na seminarium zostaną zaprezentowane także wstępne wyniki druku warstw aktywnych i opracowanych kompozycji atramentów i omówione będą perspektywy rozwoju drukowanej elektroniki organicznej.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  109. /373/
    Date: Friday 2018.03.23
    Speaker: Dr Oleksandr Bondar
    Affiliation: Sumy State University, Sumy, Ukraine
    Title: Fabrication and Investigation of Multielement and Multilayered Protective Coatings With Enhanced Physical-Mechanical and Tribological Properties Based on Nitrides of Transition Metals
    Abstract: The presentation will be devoted to investigation of structure, physical-mechanical and tribological properties of multielement NbN, Nb-Si-N, Nb-Al-N, (Ti-Zr-Hf-V-Nb)N and (Ti-Zr-Hf-V-Nb-Ta)N coatings, as well as multilayered TiN/MoN, TiN/ZrN and MoN/CrN coatings with various bilayer thickness, deposited using PVD methods (vacuum-arc evaporation of cathode or reactive magnetron sputtering). Influence of deposition conditions on microstructure and properties of the coatings will be discussed. In addition, influence of high-temperature annealing and high-dose ion implantation of Au- and N+ ions will also be covered within the presentation.
    Chair: Prof. UAM Krzysztof Grygiel
    Seminar language: English
  110. /372/
    Data: środa 2018.03.21
    Prelegent: Dr Danuta Stefańska
    Afiliacja: Wydział Fizyki Technicznej, Politechnika Poznańska
    Tytuł: Spektroskopowa analiza oddziaływań w atomach terbu i holmu jako droga do zastosowań w kwantowej inżynierii i metrologii
    Streszczenie: Tematyka wystąpienia obejmuje kompleksowe badania struktury nadsubtelnej (w wybranych przypadkach również z dodatkowym rozszczepieniem zeemanowskim) poziomów elektronowych atomu i jonu terbu oraz atomu holmu, prowadzone metodą fluorescencji wzbudzonej wiązką laserową, z użyciem jednomodowych laserów przestrajalnych. Kluczowe w badaniach jest wykorzystanie przestrajalnego lasera barwnikowego generującego w trudno dostępnym zielonym zakresie spektralnym, pompowanego optycznie laserem diodowym. Istotny postęp w analizie struktury elektronowej dla wspomnianych pierwiastków, uzyskany w oparciu o wspomniane badania eksperymentalne, może stanowić podstawę poszukiwania zastosowań w kwantowej inżynierii i metrologii. Dla atomu holmu zaproponowano schematy poziomów do pomiaru zmian czasowych stałej struktury subtelnej. Rozważane są w dalszej perspektywie również inne zastosowania dotyczące atomu terbu.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  111. /371/
    Date: Monday 2018.03.19
    Speaker: Dr Wojciech Gawełda
    Affiliation: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
    Title: Time-resolved studies of chemical reaction dynamics using ultrashort X-ray pulses (Seminarium habilitacyjne)
    Abstract: Ultrafast structural dynamics is an emerging field aiming to deliver a detailed understanding of the elementary steps in reacting chemical species, which involve changes in their nuclear, electronic and spin states. Such processes are vital ingredients in chemistry and biology, but also in technological applications, including efficient charge transport in light harvesting molecules and ultrafast switchable molecular magnets. In order to unravel this complex dynamic behavior we have implemented a suite of ultrafast X-ray spectroscopic and scattering tools to zoom into both the electronic and nuclear structures, with the goal to ultimately deliver a molecular movie of ongoing chemical processes. In view of the many potential applications in chemical and biological dynamics it is desirable to increase the sensitivity level of such experiments as well as to decrease the time resolution into the femtosecond time domain. In this talk I will present our benchmark results using a versatile setup that permits simultaneous measurements of ultrafast X-ray absorption and emission spectroscopies combined with X-ray scattering, which has been recently implemented at different synchrotrons and X-ray Free Electron Lasers. It has been applied to study different photochemical reactions, ranging from nascent radicals in solution, molecular spin transitions, and ligand exchange reactions, to photocatalytic systems, with the goal to deliver a deeper understanding of the elementary steps in chemical reactivity.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  112. /370/
    Date: Wednesday 2018.03.14
    Speaker: Dr hab. Tomasz Kwiatkowski
    Affiliation: Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University in Poznan
    Title: Where gravity no longer dominates: The internal structure and evolution of the smallest asteroids
    Abstract: Asteroids, space rocks orbiting the Sun, are very diverse in composition. While the largest of them (500-1000 km) are spheroidal bodies, and the middle-sized ones (0.1-500km) are gravity-dominated, irregular rubble-piles, the smallest asteroids (D < 0.1km) are either monolitic bodies or boulders held together by the forces of cohesion. Observations suggest that many of the smallest asteroids can be surprisingly weak bodies evolving under the influence of the solar radiation. Since some of them come close to the Earth, they can be easily observed or even visited by space probes. This way they can serve as a laboratory for testing physical phenomena controlling the evolution of the asteroids not only in our Solar System, but also those orbiting around other stars. The talk will be targeted for non-astronomers with the emphasis on the physical phenomena in the low-gravity environment. I will interpret images obtained from space probes, present shape models used for testing theories and arrive at conclusions about the internal structure and evolution of the smallest asteroids.
    Chair: Prof. UAM Agnieszka Kryszczyńska
    Seminar language: English
  113. /369/
    Date: Friday 2018.03.09
    Speaker: Prof. Andrzej Dobek
    Affiliation: Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University
    Title: THz Kerr effect in water
    Abstract: As a liquid, water plays a critical role in biological systems. Its permanent dipole moment can interact favorably with charged species. Water is an excellent hydrogen bonding solvent. It has a balanced number of hydrogen bond donors and acceptors and it has the smallest moment of inertia among small molecule polar liquids. As such it demonstrates the fastest solvent relaxation dynamics. In the liquid phase H2O molecules form a disordered fluctuating network of intermolecular hydrogen bonds. The motions of biomacromolecules depend on the structure and dynamics of water. These motions take place over a many time-scales: from ns (diffusion of H2O in the first solvation shell of protein), through ps (amino-acid side motions) to sub-ps (librational and phonon-like motion of H2O). The motions in a large range of frequencies can be studied by the OKE, the anisotropic Raman scattering and the dielectric techniques including THz-TDS. Using these methods one can observe changes in the spectra of biomacromolecules in water solution in the range 10 GHz-30 THz. In the lecture the fundamentals of THz radiation, as well as optical and THz Kerr effect will be reminded. THz–OKE measurements of three water samples of deionized, distilled and buffered (PBS) water will be reported and analyzed. These media were chosen in order to study the effect of ions presence on water behavior in the ultrafast time scale. The water most interesting from the point of view of living cells studies is the one significantly ionized. Therefore, discrimination between ultrafast effects resulting from internal H2O properties from those resulting from H2O – ions interactions are very important. These two effects may be connected to difference in the fluctuations of the network of intermolecular hydrogen bonds of water molecules in the presence or absence of ions and cations in solution. These fluctuations are expected to significantly alter water birefringence amplitude and its dynamics.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  114. /368/
    Data: Środa 2018.03.07
    Prelegent: Mgr Oleksadr Chumak
    Afiliacja: Institute of Physics, Polish Academy of Science, Warsaw
    Tytuł: Właściwości magnetosprężyste, anizotropia magnetyczna oraz właściwości dysypatywne cienkich warstw stopów Heuslera.
    Streszczenie: Na seminarium zostaną przedstawione badania cienkich warstw stopów Heuslera Co2FexMn1−xSi (CFMS) i Co2FeGa0.5Ge0.5 (CFGG). Wymienione wyżej stopy charakteryzują się wysoką polaryzacją spinową i są dobrymi kandydatami do zastosowań, między innymi w spintronice. W tych materiałach ważną rolę odgrywają ich właściwości magnetosprężyste, anizotropia magnetyczna oraz właściwości dysypatywne. Przede wszystkim rozważany jest wpływ skończonej grubości warstwy magnetycznej a także zastosowania różnych warstw buforowych oraz powierzchniowych. Będą także przedstawione badania szeregu dodatkowych parametrów charakteryzujących warstwy magnetyczne, takich jak wartości całki wymiany, uporządkowanie chemiczne oraz parametry tłumienia magnetycznego. Szczególnie zostanie przedstawiona unikatowa technika Strain Modulated Ferromagnetic Resonance (SMFMR), która umożliwia badania właściwości magnetosprężystych cienkich warstw magnetycznych.
    Przewodniczący: Prof. Maciej Krawczyk
    Seminar language: Polish
  115. /367/
    Data: środa 2018.02.21
    Prelegent: Dr Magdalena Widlicka
    Afiliacja: Department of Optics & Photonics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology
    Tytuł: Badania właściwości biomechanicznych gałki ocznej i ich zastosowania w diagnostyce oka (Seminarium habilitacyjne)
    Abstract: Tematyka seminarium obejmuje aspekty biomechaniki, optyki i dynamiki gałki ocznej mające związek z powstawaniem obrazu w układzie optycznym oka. Wykład przybliży cel naukowy badań parametrów mechanicznych tkanek oka i ich skorelowania z procesami fizjologicznymi i rozwojem patologii (w tym jaskry) w oku. Oko człowieka jest strukturą, w której występuje ścisła korelacja pomiędzy właściwościami mechanicznymi i refrakcyjnymi oka. Oznacza to, że z powodów czysto optycznych parametry strukturalne – geometryczne i materiałowe – muszą spełniać określone warunki. Określenie tych warunków umożliwia przewidywanie procesów fizjologicznych oraz diagnostycznych, w tym skutków patologii oka. Część chorób oka ma etiologię mechaniczną, do takich należy jaskra. Wiedza z zakresu mechaniki obejmuje zarówno zjawiska fizjologiczne zachodzące wewnątrz gałki ocznej, jak również efekty działań diagnostycznych. Jednym z takich działań jest procedura pomiaru ciśnienia wewnątrzgałkowego (tonometria). Wszystkie realistyczne modele gałki ocznej w tonometrii i chirurgii refrakcyjnej muszą dzisiaj uwzględniać zarówno zmienną grubość powłok oka, jak również nieliniowość ich właściwości materiałowych. Prezentowane w literaturze modele biomechaniczne oka, wykorzystywane w diagnostyce, stworzono głównie pod kątem zastosowania albo w tonometrii albo w korekcji refrakcji, natomiast nie uwzględniają one związku pomiędzy tymi dwoma zastosowaniami. Ponadto istnieją też inne czynniki/procesy fizjologiczne (np. puls oczny, akomodacja, zaćma, jaskra itp.), które należy uwzględnić w modelowaniu i diagnostyce oka. Brakuje dzisiaj kompaktowego modelu, zdolnego pełnić wszystkie powyższe funkcje. Na seminarium zaprezentowane będą wyniki badań zmierzające do określenia takiego modelu gałki ocznej.
    Prowadzący: Prof. Michał Banaszak
    Seminar language: Polish
  116. /366/
    Date: Wednesday 2018.02.14
    Speaker: Dr Jan Guzowski
    Affiliation: Instytut Chemii Fizycznej PAN, Warszawa
    Title: Structure and dynamics of droplet aggregates: from small clusters to elongated threads and large tissue-like conglomerates
    Abstract: Generation and manipulation of tiny aqueous compartments by external flow finds numerous applications in analytical sciences where each compartment (droplet) may be used as a separate chemical- or bio-reactor. In this talk I will focus on material-science perspective on droplet microfluidics in which individual compartments are treated as building blocks of larger structures. It is known that concentrated emulsions behave like soft-solids and exhibit both strong plasticity and viscoelasticity. Microfluidics opens new perspectives on studying these tissue-like materials at mesoscale: the possibility of tracking individual droplets gives a unique insight into the process of their self-assembly into ordered, reconfigurable structures. In particular, we observe a variety of small, compact clusters with well-defined point-group symetries. In presence of external flow the structures get stretched into semi-solid granular threads with long-range translational order. Finally, we study relaxation dynamics of large spheroidal aggregates composed of hundreds or thousands of droplets (10^2 </N/<10^4 ) and compare the obtained results with similar experiments on cell aggregates reported previously in the literature. We try to draw possible mechanistic analogies between droplet-based structures and actual biological micro-tissues.
    Chair: Dr Zbigniew Rozynek
    Seminar language: English
  117. /365/
    Date: Friday 2018.02.09
    Speaker: Dr Maciej Misiorny
    Affilation: Zakład Fizyki Mezoskopowej, Wydział Fizyki UAM
    Title: Spin-dependent transport of electrons trough molecular junctions in the Kondo regime (Seminarium habilitacyjne)
    Abstract: Nanojunctions containing individual impurities strongly tunnel coupled to leads have proven to be an excellent test-bed for studying quantum many body effects in electronic transport, among which the Kondo effect is one of the most prominent ones. The role of such impurities can be played, for instance, by quantum dots, magnetic atoms or molecules. A proper understanding of the effect of charge and spin correlations on electronic transport is especially sought for devices based on large-spin (S>1/2) impurities exhibiting spin anisotropy. This stems from the fact that such systems are a suitable platform for applications in emerging technologies for storage and processing information. In this talk, I will address different effects that can arise in strongly correlated spin-polarized transport through junctions with spin-anisotropic impurities. Specifically, I will discuss the influence of spin anisotropy on transport characteristics, as well as demonstrate how to control spin anisotropy of an impurity with the aid of spintronic exchange fields.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  118. /364/
    Date: Thursday 2018.02.08
    Speaker: Prof. Frederic Paul
    Affiliation: University of Rennes1/CNRS, Institute of Chemical Sciences, France
    Title: Redox-active Group Metal-Alkynyl Complexes: Toward Molecules and Materials with Electro-switchable Optical Properties
    Abstract: Over the last decade, the design of molecular structures allowing the control of a given property (electron transfer, magnetism, catalysis) using an external stimulus, such as electron-exchange, constitutes an important goal, both from the fundamental and applied standpoint. The facile and reversible M(II)/M(III) redox process exhibited by several Fe(II) and Ru(II) σ-arylacetylides fragments of formula "L4XM(C ≡ C-Ar)-" can conveniently be used to reach molecular assemblies with large and redox-switchable third-order nonlinear optical (NLO) properties such as 1 or 2 [1,2]. Finally, attempts to extend this concept to fluorescence or two-photon absorption, or to access related electroswitchable materials will be reported.

    [1] M. P. Cifuentes, M. G. Humphrey, J. P. Morall., M. Samoc, F. Paul, T. Roisnel, C. Lapinte Organometallics. 2005, 24, 4280-4288 (and refs. cited).
    [2] (a) Gauthier, N.; Argouarch, G.; Paul, F.; Toupet, L.; Ladjarafi, A.; Costuas, K.; Halet, J.-F.; Samoc, M.; Cifuentes, M. P.; Corkery, T. C.; Humphrey, M. G. Chem. Eur. J. 2011, 17, 5561. (b) N. Gauthier , C. Olivier , S. Rigaut , D. Touchard , T. Roisnel , M. G. Humphrey , F. Paul Organometallics 2007, 26, 1063.
    [3] N. Gauthier, G. Argouarch, F. Paul, M. G. Humphrey, L. Toupet, Ababou-Girard, S., H. Sabbah, P. Hapiot, B. Fabre, Adv. Mater. 2008, 20, 1952.
    Chair: Prof. UAM Jacek Kubicki
    Seminar language: English
  119. /363/
    Date: Wednesday 2018.02.7
    Speaker: Dr Arkadiusz Matwijczuk
    Affiliation: Department of Physics, University of Life Sciences in Lublin
    Title: Organizacja molekularna 1,3,4-tiadiazaoli z funkcją 2,4-dihydroksyfenylu w rozpuszczalnikach organicznych oraz w układach modelowych o znaczeniu biologicznym
    Abstract: [PDF]  Wybrane do badań właściwości fotofizycznych związki z grupy 1,3,4-tiadiazoli wykazują głównie działanie neuroprotekcyjne, przeciwgrzybiczne oraz antynowotworowe. Badania spektroskopowe związków wykonane metodami spektroskopii molekularnej pozwoliły zaobserwować, w przypadku części struktur w środowisku wodnym, bardzo interesujące zjawisko podwójnej fluorescencji. Efekt ten może być indukowany zmianą pH roztworów wodnych, temperatury oraz efektami agregacyjnymi. W przypadku analogicznych pomiarów widm związków wykonanych w różnych rozpuszczalnikach organicznych, obserwowano tylko pojedyncze pasmo fluorescencji. Badania różnych analogów tej grupy związków wykazały, że można indukować wyżej wymieniony efekt również w rozpuszczalnikach oraz modelowych układach biologicznych poprzez zmianę stężenia związku lub modyfikację jego podstawnika. W wodnych roztworach metanolu o określonej kwasowości obserwowano najczęściej dwa osobne, częściowo pokrywające się, pasma fluorescencji. W oparciu o dane krystalograficzne i badania fluorescencyjne monokryształów związków stwierdzono, że mogą one przyjmować dwie konformacje w zależności od orientacji przestrzennej grupy -OH znajdującej się w pozycji orto względem pierścienia tiadiazolowego. W zależności od przyjmowanej konformacji w widmach emisji obserwujemy efekt podwójnej fluorescencji lub dwa częściowo pokrywające się pasma emisji. Szereg badań wykonanych metodami spektroskopowymi takimi jak technika RLS, pomiary czasów życia fluorescencji oraz pomiary widm emisji i wzbudzenia fluorescencji wskazują, że w wyjaśnieniu natury zaobserwowanych efektów fluorescencyjnych pomocna jest zarówno wiedza na temat konformacji molekuł jak i występowania efektów agregacyjnych w roztworze. Układ w którym cząsteczki przyjmują konformację z grupą -OH z pierścienia rezorcylowego ustawioną bliżej atomu azotu z pierścienia 1,3,4-tiadiazolowego prawdopodobnie zwiększa możliwość wewnątrzmolekularnego przeniesienia ładunku i powstawania słabego stanu elektronowego związanego z tym przeniesieniem, prowadzącego w konsekwencji do powstawania efektu podwójnej fluorescencji tych cząsteczek, co potwierdzają obliczenia kwantowomechaniczne metodami [TD]DFT. Obie obserwowane konformacje odpowiednio stabilizowane przypuszczalnie może różnić też zdolność oddziaływań biologicznych. Warto podkreślić, że badania biologiczne tej grupy związków wykazały również grzybobójcze efekty synergistyczne z amfoterycyną B w stosunku do kilku szczepów grzybów patogennych w hodowlach in vitro.
    Chair: Prof. Maciej Krawczyk
    Seminar language: Polish
  120. /362/
    Data: poniedziałek 5.02.2018
    Prelegent: Mgr Daria Larowska
    Afiliacja: Zakład Fizyki Chemicznej, Wydział Chemii UAM
    Tytuł: Fotokatalityczny rozkład wody w układach barwnik /tlenek grafenu/ kompleks kobaltu.
    Streszczenie: Konwersja energii słonecznej na energię w formie paliwa wydaje się być jednym z najbardziej obiecujących sposobów na zaspokojenie potrzeb energetycznych świata w przyszłości. Szczególnie duże nadzieje pokładane są w rozkładzie wody (water splitting) prowadzącym do gospodarki opartej na wodorze jako podstawowym paliwie. Opracowanie taniej, wydajnej i szybkiej metody produkcji wodoru, jest podstawowym warunkiem, który musi być spełniony by wodór mógł zastąpić bieżące nośniki energii. Obecne metody wykorzystywane do kierowanego światłem rozkładu wody podzielone mogą zostać na trzy grupy: metody termochemiczne, fotobiologiczne oraz fotokatalityczne. W ramach seminarium omówiona zostanie koncepcja fotokatalitycznej dekompozycji wody w układach barwnik/ tlenek grafenu/kompleks kobaltu – ich charakterystyka, właściwości oraz metodologia badań. Powierzchnia tlenku grafenu dzięki jego unikalnym właściwościom może zostać sfunkcjonalizowana za pomocą cząsteczek oraz nanomateriałów. Główna korzyść zastosowania takich hybryd wiąże się zachodzącym w nich transportem elektronu od wzbudzonej cząsteczki barwnika do katalizatora kobaltowego poprzez arkusz tlenku grafenu (GO), w wyniku czego następuje redukcja protonów i utworzenie wodoru cząsteczkowego.
    Prowadzący: Prof. UAM Marcin Ziółek
    Seminar language: Polish
  121. /361/
    Date: Friday 2018.02.2
    Speaker: Dr Jadwiga Nieminuszczy
    Affiliation: Division of Cancer Biology, Institute of Cancer Research, London, UK
    Title: EXD2 nuclease safeguards the genome against replicative stress
    Abstract: The maintenance of replication fork stability is essential for faithful genome duplication and suppression of carcinogenesis. In an effort to further our understanding of the mechanism of replication fork repair we performed an analysis of proteins recruited to DNA replication forks using the iPOND technique. This analysis identified EXD2, a nuclease that we have shown recently to promote DNA-end resection and homology-directed repair1, as a novel factor present at replication forks. EXD2 is required for efficient ATR activation and fork restart in response to replicative stress. Moreover, purified recombinant EXD2 can efficiently process synthetic DNA structures mimicking those that are generated at stalled/collapsed replication forks. In keeping with this, EXD2-deficient cells are sensitive to a plethora of agents that interfere with replication fork progression. Failure to timely complete DNA synthesis leads to the persistence of under-replicated DNA, which can manifest as anaphase bridges, 53BP1 OPT domains and/or cause formation of micronuclei. Consistent with EXD2’s role in promoting efficient genome duplication, we observe that EXD2-deficient or EXD2-nuclease dead cells display a significant increase in the frequency of all these markers. Thus, our data identify EXD2 as a novel component of the replication fork protection pathway. We propose that EXD2 processes stalled/collapsed replication forks and by doing so, promotes efficient fork restart assuring accurate completion of DNA replication.
    [1] R. Broderick et al., EXD2 promotes homologous recombination by facilitating DNA end resection, Nat Cell Biol 18, 271-280 (2016).
    Chair: Dr Paweł Zawadzki
    Seminar language: English
  122. /360/
    Date: Wednesday 2018.01.31
    Speaker: Dr Piotr Korcyl
    Affiliation: Wydział Fizyki, Astronomii i Informatyki Stosowanej Uniwersytetu Jagiellońskiego
    Title: Using perturbation theory for non-perturbative calculations
    Abstract: Nowadays many inputs of phenomenological models are taken from lattice simulations of Quantum Chromodynamics. These numerical methods, based on Monte Carlo techniques, always stress their superiority against other approaches by arguing that all steps of computations are from first principles and truly non-perturbative. However many of the most precise results use in one way or another perturbation theory. In this talk I will try to explain the intertwinned relation between non-perturbative simulations and perturbation theory and discuss some of the modern techniques of getting perturbative results on a lattice.
    Chair: dr hab. Krzysztof Cichy
    Seminar language: English
  123. /359/
    Data: środa 24.01.2018
    Prelegent: Prof. UAM Gotard Burdziński
    Afiliacja: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
    Tytuł: Osobliwości naukowe roślin
    Streszczenie: W ramach seminarium zostaną omówione wybrane metody obronne roślin takie jak szybki ruch związany ze składaniem liści, wytwarzaniem substancji trujących, lub zapachu, który przywabia owady drapieżne. Szczególna uwaga zostanie poświęcona roślinom owadożernym, których ruch pułapkujący bywa zaskakująco szybki (w czasie ok. 3 ms u Ultricularia inflata), co wymaga stosowania szybkich kamer (15000 klatek na sekundę). Omówione zostaną również aspekty związane z powabnością kwiatów zarówno w zakresie akustyki (liść o kształcie czaszy stanowi akustyczną echo-latarnię dla nietoperzy zapylających kwiaty Marcgravia evenia), jak i optyki (ubarwienie strukturalne płatków kwiatowych). Główną rolę ubarwienia kwiatów pełnią barwniki, spośród których dla betalain wykazaliśmy funkcję fotoprotekcyjną.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  124. /358/
    Data: poniedziałek 22.01.2018
    Prelegent: Dr hab. Tomasz Grzyb
    Afiliacja: Zakład Ziem Rzadkich, Wydział Chemii UAM
    Tytuł: Up-konwersja w nanomateriałach domieszkowanych jonami lantanowców: synteza, właściwości strukturalne i spektroskopowe
    Streszczenie: Luminescencja jonów lantanowców (Ln3+) jest tematem intensywnych badań, ze względu na rosnące zapotrzebowanie domieszkowanych nimi materiałów w wielu dziedzinach. W odpowiednio zaprojektowanych materiałach luminescencja jonów Ln3+ jest wydajna i intensywna, a przede wszystkim możliwe jest uzyskanie procesu konwersji energii w górę - up-konwersji (UC, ang. up-conversion). Zjawisko to odpowiada nieliniowemu procesowi absorpcji dwóch lub większej ilości fotonów w wyniku której następuje emisja promieniowania o energii wyższej niż zaabsorbowanego. Od kilku lat obserwuje się wzrost zainteresowania nanocząstkami wykazującymi UC, głównie ze względów na szerokie zastosowania w medycynie i biologii. Jednymi ze związków charakteryzującymi się właściwościami umożliwiającymi uzyskanie UC są nieorganiczne fosforany, wanadany i fluorki. Odpowiednia metoda syntezy, środowisko reakcji oraz dobór reagentów umożliwiają uzyskanie produktów o niewielkim rozmiarze krystalitów (< 50 nm). Otrzymano szereg nanomateriałów opartych o związki typu REPO4, REVO4, SrF2, LuF3, NaLuF4 oraz MRE2F7 (gdzie M = Ca, Sr, Ba; RE = Y, La, Gd, Lu), domieszkowanych jonami Yb3+ i Ho3+, Er3+, Tm3+, Tb3+ lub Eu3+. Otrzymane produkty scharakteryzowano pod względem ich struktury i morfologii oraz składu pierwiastkowego. Najważniejszym elementem przeprowadzonych badań było określenie właściwości spektroskopowych otrzymanych materiałów. W celu otrzymania pełnej charakterystyki luminescencyjnej otrzymanych produktów wykonano pomiary widm wzbudzenia (także w zakresie podczerwieni) oraz emisji, a także zaników emisji oraz zależności intensywności luminescencji od mocy (lub energii) promieniowania wzbudzającego. Pozwoliło to na poznanie procesów zachodzących w otrzymanych materiałach, zaproponowanie mechanizmów tych procesów, a także na optymalizację badanych układów pod względem intensywności luminescencji.
    Prowadzący: Prof. UAM Marcin Ziółek
    Seminar language: Polish
  125. /357/
    Date: Wednesday 2018.01.17
    Speaker: Prof. Matteo Rizzi
    Affiliation: Johannes Gutenberg-Universität, Institut für Physik, Mainz, Germany
    Title: Exploring Interacting Topological Insulators with Ultracold Atoms: the Synthetic Creutz-Hubbard Model
    Abstract: Understanding the robustness of topological phases of matter in the presence of strong interactions, and synthesising novel strongly-correlated topological materials, lie among the most important and difficult challenges of modern theoretical and experimental physics. The synthetic Creutz-Hubbard ladder is a paradigmatic model that provides a neat playground to address these challenges, including the generation of flat bands as well as of non-doubled Dirac dispersion relations. In [1], we present a theoretical analysis of the competition between correlated topological phases and orbital quantum magnetism in the regime of strong interactions at half-filling. We predict topological quantum phase transitions for weak and intermediate interactions with different underlying conformal field theories (CFTs), i.e. Dirac versus Majorana CFTs. In [2], we study the response of an interacting system of Dirac-Weyl fermions confined in a one-dimensional (1D) ring: we show that tuning of interactions leads to a unique many-body system that displays either a suppression or an enhancement of the Drude weight—the zero-frequency peak in the ac conductivity—with respect to the non-interacting value. Both studies are furthermore confirmed and extended by extensive numerical simulations based on matrix product states (MPS) and binary Tree Tensor Networks (bTTN). Moreover we propose how to experimentally realize this model in a synthetic ladder, made of two internal states of ultracold fermionic atoms in a one-dimensional optical lattice.

    [1] J. Jünemann, et al., PRX 7, 031057 (2017)
    [2] M. Bischoff, et al., arXiv:1706.02679
    Chair: Dr Agnieszka Cichy
    Seminar language: English
  126. /356/
    Data: Poniedziałek 2018.01.15
    Prelegent: Prof. UAM Ireneusz Weymann
    Afiliacja: Zakład Fizyki Mezoskopowej, Wydział Fizyki UAM
    Tytuł: Seminarium profesorskie
    Streszczenie: Podczas seminarium ogólnie omówię tematykę moich badań, która dotyczy teoretycznej analizy własności transportowych skorelowanych układów nanoskopowych. Następnie, bardziej szczegółowo, przedstawię kilka najważniejszych zagadnień, którymi zajmowałem się po uzyskaniu stopnia naukowego doktora habilitowanego. W szczególności przedstawię rezultaty dotyczące badania różnych egzotycznych stanów Kondo w złożonych układach kropek kwantowych, omówię także badania dotyczące stanów związanych Andreeva w hybrydowych układach nanoskopowych, a także badania związane z kwazicząstkami Majorany.
    Prowadzący: Prof. Adam Miranowicz
    Seminar language: Polish
  127. /355/
    Data: Środa 2018.01.10
    Prelegent: Prof. Marcin Molski
    Afiliacja: Zakład Chemii Teoretycznej, Wydział Chemii UAM
    Tytuł: Kwantowe Fenomenologiczne Uniwersalia
    Streszczenie: Koncepcja fenomenologicznych uniwersaliów wprowadzona przez Castorinę, Delsanto i Guiot (CDG) [1], umożliwia generowanie funkcji i modeli opisujących ewolucję w czasie układów biologicznych, takich jak organy, organizmy, ekosystemy, czy nowotwory. W zależności od stopnia złożoności (nieliniowości) można badane układy sklasyfikować jako U0, U1 i U2, którym odpowiadają funkcje biologicznego wzrostu: eksponent (U0), Gompertza (U1), Westa-Browna-Enquista, Richardsa i von Bertalanffy’ego (U2). Referat prezentuje prostą modyfikację klasycznego schematu CDG [2,3], która pozwala na uzyskanie kwantowych rozwiązań równań Schrödingera i Feinberga-Horodeckiego dla oscylatora harmonicznego oraz oscylatorów anharmonicznych, reprezentujących klasy Q0, Q1 i Q2 fenomenologicznych uniwersaliów. Uogólnione podejście CDG umożliwia również wygenerowanie lokalnych i nielokalnych stanów koherentnych oscylatorów, które minimalizują zasadę nieoznaczoności Heisenberga: położenie-pęd i czas-energia. Analiza otrzymanych wyników dowodzi [2,3], że przejście od rozwiązań kwantowych Qn do klasycznych Un dla n=1,2 zachodzi dla stanu dysocjacji oscylatora. Wtedy funkcje kwantowe przechodzą w klasyczne, otrzymane w podejściu CDG, co uzasadnia nadaną im nazwę - rozwiązania quasi-kwantowe. Należą do nich wszystkie najważniejsze czasowo-zależne modele opisujące ewolucję układów biologicznych oraz przestrzenno-zależne funkcje opisujące skumulowaną dystrybucję obiektów, różniących się rozmiarem (np. średnicą aksonów w włóknie nerwowym).
    [1] P. Castorina, P. P. Delsanto, C. Guiot, Physical Review Letters 96 (2006) 188701.
    [2] M. Molski, Physics Letters A 381 (2017) 2629–2635.
    [3] M. Molski, Physics Letters A 382 (2018) 79–84.
    Prowadzący: Prof. Zbigniew Jacyna-Onyszkiewicz
    Seminar language: Polish
  128. /354/
    Data: środa 20.12.2017
    Prelegent: Dr inż. Leszek Kasprzyk
    Afiliacja: Instytut Elektrotechniki i Elektroniki Przemysłowej, Politechnika Poznańska
    Tytuł: Analiza pracy magazynów energii w pojazdach elektrycznych
    Streszczenie: W ramach seminarium zostaną omówione wybrane metody modelowania pracy akumulatorów oraz superkondensatorów w stanach dynamicznych, a także metody estymacji parametrów modelu. Poruszona zostanie krótko problematyka energochłonności pojazdów oraz metody doboru akumulatorów do zasięgu i dynamiki jazdy. W referacie zaprezentowane zostaną również przykładowe wyniki badań energochłonności pojazdu, analizy pracy akumulatorów oraz metody wydłużenia żywotności akumulatorów z wykorzystaniem rozwiązań hybrydowych.
    Prowadzący: dr hab. J. W. Kłos
    Seminar language: Polish
  129. /353/
    Date: Wednesday 2017.12.13
    Speaker: Dr Agnieszka Cichy
    Affiliation: Solid State Theory Division, Faculty of Physics, AMU
    Title: Classical and quantum simulations with ultracold 4-component fermionic mixtures in optical lattices
    Abstract: The impressive development of experimental techniques in ultracold quantum degenerate gases of alkaline-earth-like atoms in the last years has allowed investigation of strongly correlated systems. Long-lived metastable electronic states in combination with decoupled nuclear spin give the opportunity to study the Hamiltonians beyond the possibilities of current alkali-based experiments. Ytterbium is particularly convenient due to its large number of bosonic and fermionic (e.g. Yb-173) isotopes with a wide range of interaction strengths. In [1] we study finite-temperature properties of ultracold four-component mixtures of alkaline-earth-metal-like atoms in optical lattices that can be effectively described by the two-band spin-1/2 Hubbard model including Hund's exchange coupling term. Our main goal is to investigate the effect of exchange interactions on finite-temperature magnetic phases for a wide range of lattice fillings. We use the dynamical mean-field theory approach and its real-space generalization to obtain finite-temperature phase diagrams including transitions to magnetically ordered phases. It allows to determine optimal experimental regimes for approaching long-range ferromagnetic ordering in ultracold gases. We also calculate the entropy in the vicinity of magnetically ordered phases, which provides quantitative predictions for ongoing and future experiments aiming at approaching and studying long-range ordered states in optical lattices. In [2] we study the thermodynamic properties of four-component fermionic mixtures described by the Hubbard model using the dynamical mean-field-theory approach. Special attention is given to the system with SU(4)-symmetric interactions at half filling, where we analyze equilibrium many-body phases and their coexistence regions at nonzero temperature for the case of simple cubic lattice geometry. We also determine the evolution of observables in low-temperature phases while lowering the symmetry of the Hamiltonian towards the two-band Hubbard model. This is achieved by varying interflavor interactions or by introducing the spin-flip term (Hund's coupling). By calculating the entropy for different symmetries of the model, we determine the optimal regimes for approaching the studied phases in experiments with ultracold alkali and alkaline-earth-like atoms in optical lattices.

    [1] A. Cichy, A. Sotnikov, Phys. Rev. A 93, 053624 (2016)
    [2] A. Golubeva, A. Sotnikov, A. Cichy, J. Kuneš, W. Hofstetter, Phys. Rev. B 95, 125108 (2017)
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  130. /352/
    Date: Monday 2017.12.11
    Speakers: Dr Mateusz Gierszewski & M. Sc. Eng. Iwona Grądzka
    Affiliation: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
    Title: Wybrane zagadnienia konwersji energii słonecznej z konferencji ICP i ISPPCC 2017
    Chair: Prof. UAM Marcin Ziółek
    Seminar language: Polish
  131. /351/
    Date: Wednesday 2017.12.06
    Speaker: Dr Michał Michałowski
    Affiliation: Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University in Poznan
    Title: The first observation of radiation from colliding neutron stars – the sources of gravitational waves
    Chair: Prof. UAM Agnieszka Kryszczyńska
    Seminar language: English
  132. /350/
    Date: Wednesday 2017.11.29
    Speaker: Dr Jaroslaw Paturej
    Affiliation: Institute of Physics, University of Szczecin
    Title: How macromolecular architecture affects physical properties of polymers
    Abstract: [PDF]  Significant progress in polymerization techniques allows to synthesize macromolecules with complex, yet precisely controlled structure. Three distinct examples are branched bottlebrushes, star polymers and ring-like polymers. During the talk I will demonstrate that variation of macromolecular architecture affects structural, mechanical, interfacial and frictional properties of polymers as compared to conventional linear chains.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  133. /349/
    Date: Wednesday 2017.11.22
    Speaker: Prof. Igor Lyubchanskii
    Affiliation: Donetsk Physical and Technical Institute of the National Academy of Sciences of Ukraine and Department of Physics and Technology, Donetsk National University
    Title: Static magneto-optic effects in photonic-magnonic crystals
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  134. /348/
    Date: Wednesday 2017.11.15
    Speaker: Prof. Konstantin Guslienko
    Affiliation: Universidad Del Pais Vasco/Euskal Herriko Unibertsitatea, San Sebastian, Spain
    Title: Skyrmion stability and dynamics in ultrathin magnetic dots
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  135. /347/
    Date: Tuesday 2017.11.14
    Speaker: Dr Junghee Ryu
    Affiliation: Centre for Quantum Technologies, National University of Singapore, Singapore
    Title: Operational quasiprobabilities in quantum theory
    Abstract: Negative probability was introduced by Feynman to address a mystery of quantum theory [1]. Since then there have been many studies based on such approach. But from the point of view of the operationalism, there are conceptual problems of interpreting such probability with respect to a given physical situation. In other words, the meaning of the negative values is not clear. Recently, an operational quasiprobabilities (OQs) are introduced for qudits as well as optical fields states [2,3]. Here, we will discuss how the OQs deal with those problems.
    [1] R. Feynman, in Negative Probabilities in Quantum Mechanics, edited by B. Hiley and F. Peat (Routledge, London, 1987).
    [2] J. Ryu, J. Lim, S. Hong, and J. Lee, Operational quasiprobabilities for qudit, Phys. Rev. A 88, 052123 (2013).
    [2] J. Jae, J. Ryu, and J. Lee, Operational quasiprobabilities for continuous variables, Phys. Rev. A 96, 042121 (2017).
    Chair: Dr hab. Paweł Kurzyński
    Seminar language: English
  136. /346/
    Date: Thursday 2017.11.9
    Speaker: Dr Koji Maruyama
    Affiliation: Osaka City University, Osaka, and Waseda University, Tokyo, Japan
    Title: Hilbert space structure induced by limited access
    Abstract: Having seen the possibility of controlling multi-body quantum systems indirectly, as well as that of identifying the entire Hamiltonian, now let us consider a more fundamental/abstract problem. When our direct access, or the number of (direct) control probes, to the system is limited, what is the extent to which it can be identified/controlled? This is a natural question, especially after realising that there are (infinitely) many systems that cannot be distinguished via restricted access. In our attempt to understand the intrinsic origin of the indistinguishability, we have revealed the characteristic structures of Hilbert space that is induced by the limited access. The structure tells us what draws the line between controllable and uncontrollable subsystems, which necessarily leads to indistinguishability as well.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  137. /345/
    Date: Wednesday 2017.11.8
    Speaker: Dr Koji Maruyama
    Affiliation: Wolfram Research, Japan
    Title: Machine Learning by Mathematica (Wolfram Language)
    Abstract: The machine learning functionality has been significantly augmented in Mathematica 11. There are a number of functions that allow us to start machine learning quickly without expertise in this field. At the same time, it provides us with a rich set of components to build up more complex tools, such as deep neural networks. I will show how Mathematica can be used to carry out machine learning computations for various types of data sets.
    Chair: Prof. Adam Miranowicz
  138. /344/
    Date: Wednesday 2017.11.8
    Speaker: Dr Koji Maruyama
    Affiliation: Osaka City University, Osaka, and Waseda University, Tokyo, Japan
    Title: Two-qubit control suffices to efficiently perform quantum computation on a spin chain
    Abstract: Towards the full manipulation of multi-body quantum systems, there are still a number of obstacles we have to overcome. We would need some tricks when taming a complex quantum system, contemplating what we can do and what we cannot. In this talk, I will delineate a theoretical guiding principle for quantum controllability, and will present a specific idea for controlling a spin system with a highly limited access. Three important issues, i.e., the controllability, the computability of pulse sequence, and the time-scale of quantum computing operations, are addressed and answered positively.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  139. /343/
    Date: Tuesday 2017.11.07
    Speaker: Dr Taras Radchenko
    Affiliation: Department of Solid State Theory, Institute for Metal Physics, National Academy of Sciences of Ukraine, 03142 Kyiv, Ukraine
    Title: Electronic and transport properties of (un)strained graphene with structural defects: Numerical calculations
    Abstract: The study deals with modelling electronic and transport properties of unstrained and uniaxially deformed graphene with structural imperfections: zero-dimensional (point) and one-dimensional (extended) defects. Point defects are modelled as resonant (neutral) adsorbed atoms or molecules, vacancies, charged impurities, and local distortions. Extended (line) defects are attributed to atomic steps and terraces in epitaxially-grown graphene, and grain boundaries, quasi-periodic nanoripples or wrinkles in polycrystalline (chemically vapor-deposited) graphene. Results are obtained numerically using the quantum-mechanical Kubo-Greenwood formalism along with tight-binding approach. Calculated behaviours of electronic density of states and conductivity indicate that deviations from perfection can be useful: they make possible tailoring graphene's electrotransport properties for achievement of new functionalities.
    Chair: dr Mateusz Kempiński
    Seminar language: English
  140. /342/
    Date: Monday 2017.11.06
    Speaker: Dr Andriy Khobta
    Affiliation: Unit “Responses to DNA Lesions”, Institute of Toxicology, University Medical Center Mainz
    Title: Exploiting synthetic DNA lesions to pinpoint the critical repair pathways
    Abstract: [PDF]  DNA damage is a well-recognised causal factor of gene dysfunction in cancers and age-related diseases. Because DNA of all living cells is constantly exposed to a variety of reactive endogenous metabolites and environmental toxicants, DNA damage can never be fully avoided and its complexity comprises dozens of structurally different DNA modifications ("DNA lesions"). Knowledge of the lesion-specific responses of cells is required to characterise hazards of exposure to specific genotoxic agents and, from the translational perspective, to identify molecular susceptibility markers and potential targets for personalised therapeutic interventions.
    My team exploits synthetic nucleotide derivatives to understand harmful consequences of individual DNA lesions and the lesion-specific repair mechanisms. To model damage induced by food carcinogens, drugs, environmental toxicants and endogenous cellular mechanisms at specific nucleotide positions, we incorporate synthetic analogs of the respective DNA modifications as building blocks into functional reporter genes [1-2]. Delivered to human host cells, such gene constructs can be efficiently used to monitor functional consequences of defined DNA lesions (tolerance versus toxicity), to characterise determinants of damage recognition by individual repair pathways, and to identify redundancy and potential switch points between the pathways [3-7]. I will discuss some recent applications of vectors containing the elements of synthetic nucleic acids to address questions in the fields of DNA repair and epigenetics.
    [1] Lühnsdorf B, et al. (2012) Analytical Biochemistry 425: 47-53
    [2] Kitsera N, et al. (2011) Nucleic Acids Research 39: 5926-5934
    [3] Kitsera N, et al. (2014) PloS One 9: e94405
    [4] Allgayer J, et al. (2013) Nucleic Acids Research 41: 8559-8571
    [5] Lühnsdorf B, Epe B, Khobta A (2014) The Journal of Biological Chemistry 289: 22008-22018
    [6] Allgayer J, et al. (2016) Nucleic Acids Research 44: 7267-7280
    [7] Kitsera N, et al. (2017) Nucleic Acids Research doi: 10.1093/nar/gkx718 [Epub ahead of print].
    Chair: Dr Paweł Zawadzki
    Seminar language: English
  141. /341/
    Date: Wednesday 2017.10.25
    Speaker: Dr Paweł Zawadzki
    Affiliation: Molecular Biophysics Division, Faculty of Physics, AMU
    Title: Single-molecule imaging of DNA repair in single living cells
    Abstract: [PDF]  Every single day an individual cell must deal with ~10,000 lesions in order to prevent accumulation of harmful mutations, which might lead to cancer. Understanding the mechanism of DNA repair is therefore of central importance to our understanding of cancer and for the development of new therapeutics against it. Repair pathways are highly conserved, in both prokaryotes and eukaryotes, and studying the simpler pathways in bacteria provides key insight into the mechanism used by human cells to repair damaged DNA. We apply an interdisciplinary approach to understand the mechanistic details of DNA repair pathways (Nucleotide Excision Repair, Mismatch Repair, Base Excision Repair) in living Escherichia coli (and human cells in near future). We use a combination of cutting-edge single-molecule methods to elucidate how repair enzymes participate in removal of damaged nucleotides. Firstly, live super-resolution microscopy combined with single-particle tracking is used to study the behaviour of individual proteins as they scan the genome and repair damaged DNA. To complement this, we use cell biology, genetics and TIRF microscopy to verify and extend the conclusions established using a super-resolution microscopy. Together, this will provide a comprehensive understanding of the bacterial repair pathway, and constitute a starting point to understanding the way mutations in human repair proteins contribute to the development of cancer.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  142. /340/
    Data: środa 2017.10.18
    Prelegent: Dr Anna Marciniak
    Afiliacja: Obserwatorium Astronomiczne, Wydział Fizyki UAM
    Tytuł: Pierścień wokół planety karłowatej Haumea oraz jej rozmiary, kształt i gęstość z obserwacji zakrycia gwiazdowego
    Streszczenie: Na seminarium omówione zostaną wyniki badań opublikowane w ostatnim numerze Nature 550, 219 (2017)  w artykule pt. The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.
    Prowadząca: prof. UAM Agnieszka Kryszczyńska
    Seminar language: Polish
  143. /339/
    Date: Thursday 2017.10.12
    Speaker: Doc. Jan Soubusta
    Affiliation: Institute of Physics of Academy of Science of the Czech Republic, Joint Laboratory of Optics of PU and IP AS CR, Olomouc, Czech Republic
    Title: Experimental tests of coherence and entanglement conservation
    Abstract: In the year 2015, Svozilík and co-authors published a paper [Phys. Rev. Lett. 115, 220501 (2015)] discussing migration of coherence of the studied system between its subsystems. The authors showed that the coherence is also linked to the correlations between the subsystems. The authors mentioned a few interesting examples, where it is possible to study conservation of the maximal accessible coherence in the system. We want to demonstrate the effect of migration of coherence of the system on two experimental schemes implemented using polarization states of photons. The first scheme is based on linear optical controlled-phase quantum gate and the second scheme is utilizing effects of nonlinear optics.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  144. /338/
    Date: Thursday 2017.10.12
    Speaker: Doc. Karel Lemr
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Building a quantum router for discrete photons using linear optics
    Abstract: The talk discusses our experimental implementation of a linear-optical quantum router. This device allows single-photon polarization-encoded qubits to be routed coherently into two output modes. Routing is programmed by two identical control qubits and over this procedure, the quantum information stored in the state of the routed photon is not disturbed. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router known to this date.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  145. /337/
    Date: Thursday 2017.10.12
    Speaker: Dr Antonín Černoch
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Experimental characterization of photon-number noise in Rarity-Tapster-Loudon-type interferometers
    Abstract: We develop a simple model describing inherent photon-number noise in Rarity-Tapster-Loudon-type interferometers. This noise is caused by generating photon pairs in the process of spontaneous parametric down-conversion and adding a third photon by attenuating the fundamental laser mode to the single-photon level. We experimentally verify our model and present resulting signal-to-noise ratios as well as obtained three-photon generation rates as functions of various setup parameters.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  146. /336/
    Date: Wednesday 2017.10.11
    Speaker: Dr Alexander Mikkelsen
    Affiliation: Faculty of Physics, Adam Mickiewicz University
    Title: Droplets covered by particles: Physics and applications
    Abstract: [PDF]  Clay and colloidal particles of nano- and micrometer size adsorb strongly at liquid interfaces where they display a wide range of studies and applications [1],[2], for instance to stabilize emulsions, in material development and to encapsulate, store and release a range of materials such as medicine, cells, food or oil. Structuring of particles on droplets is a particularly hot topic these days with increasing interest and efforts devoted to the synthesis of functional colloidal capsules. Such capsules, with tailored physical, chemical or morphological characteristics, can be used as building blocks to prepare complex structures with advanced and novel material properties [3]. The talk will demonstrate and explain how weakly conductive (leaky-dielectric) droplets behave when suspended in another weakly conducive fluid and subjected to an external electric field. Especially how electrohydrodynamic and eletrorheological effects in such droplets can be used to structure and dynamically control colloidal particle assemblies at droplet surfaces. This includes electric-field-assisted convective assembly of jammed colloidal “ribbons”, electrorheological colloidal chains confined to a two-dimensional surface and spinning colloidal domains. In addition, the talk will demonstrate the size control of “pupil” like openings in colloidal shells [4], present a simple and robust method to assemble colloidal shells of controlled heterogeneity [5] and discuss some of the many applications for particle covered droplets.
     [1] B. P. Binks, Curr. Opin. Colloid In. 7, 21 (2002).
     [2] C. Zeng, H. Bissig, and A. D. Dinsmore, Solid State Commun. 139, 547 (2006).
     [3] B Bollhorst, T., K. Rezwan, and M. Maas, Chemical Society Reviews, 46, 2091 (2017).
     [4] P. Dommersnes, Z. Rozynek, A. Mikkelsen, R. Castberg, K. Kjerstad, K. Hersvik, and J. O. Fossum, Nat. Commun. 4, 2066 (2013).
     [5] Z. Rozynek, A. Mikkelsen, P. Dommersnes, and J. O. Fossum, Nat.Commun. 5, 3945 (2014).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  147. /335/
    Date: Wednesday 2017.10.4
    Speaker: Dr Zbigniew Rozynek
    Affiliation: Institute of Acoustics, Faculty of Physics, UAM
    Title: Granular and colloidal 1D structures: Physics and applications
    Abstract: [PDF]  The fabrication of 1D granular and colloidal materials is of considerable interest as they offer opportunities for a variety of electronic applications, including granular conductors, flexible electronics for wearable devices, electromagnetic energy transport, etc. These particle structures can be assembled either from particle groups or from individual particles. In this talk I will show structures composed of individual microparticles. There are several methods for fabricating particle structures, including lithography, cluster-assisted assembly and colloidal polymerization, pore-assisted assembly, and field-directed assembly in electro- or magneto-rheological fluids. The latter is generally considered to be a simple and effective approach to form particle structures. Thou fast and efficient, the external field-driven approach suffers from three major limitations to its applications, for example in electronic-device manufacturing. First, the assembly often takes place in a bulk liquid; it is difficult to remove the bulk liquid and maintain the assembled structure intact. Second, in principal only linear 1D structures can be formed along the field lines and positioning of the formed structure is greatly limited. Third, maintaining the formed structures normally requires a continuous energy supply; once the external field is turned off, the structures disintegrate. Within this talk, I will present novel routes to overcoming these limitations, making it possible to easily fabricate self-sustained 1D structures outside of a dispersion.
    For more details, see the following article: Formation of printable granular and colloidal chains through capillary effects and dielectrophoresis, Nature Communications 2017, 8, 15255 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  148. /334/
    Date: Wednesday 2017.09.27
    Speaker: Dr Łukasz Laskowski
    Affiliation: Department of Microelectronics and Nanotechnology, Częstochowa University of Technology
    Title: Practical application for porous silica template functional nanomaterials
    Abstract: [PDF]  The presentation will be devoted to novel functional nanomaterials precisely tailored for specific applications. The materials are based on porous silica matrices both in the form of powder and vertically aligned thin films. Powdered SBA-15 silica activated by copper ions can play a role of strongly antimicrobial specimen with restricted migration into environment. Thin film form of silica matrices with vertically aligned channels makes the materials highly applicative in electronics or IT technologies. We consider three types of such silica-templated materials for application as antimicrobial specimen or electronics elements. Porous silica films containing permanent magnetic specimen inside pores can be used for fabrication of super-dense magnetic memory. When silica is activated by individual molecular magnets in pores bottom the material can play a role of layout of molecular neurons. Porous silica thin layer containing strongly dipolar units have strong non-linear optical (NLO) response, that can be tuned by means of functional groups concentration variation.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  149. /333/
    Date: Monday 2017.09.25
    Speaker: Prof. David Sherratt
    Affiliation: Department of Biochemistry, University of Oxford, UK
    Title: How one chromosome makes two
    Abstract: [PDF]  Chromosomes were first observed and the process of their segregation in mitosis described by Walther Flemming, working in Kiel, Germany, in 1878, but it was another 25 years before their role in inheritance was proposed. The coordinated processes of chromosome replication, unlinking and subsequent chromosome segregation underlie the life process. Defects in these processes lead to genetic diseases and a multitude of pathologies in humans, while interfering with these processes is the basis of the action of many antibiotics and anti-cancer agents.
    My laboratory studies the molecular mechanisms of the action of the molecular machines that act in these processes in the bacterium E. coli by using a combination of in vivo and in vitro biochemistry, quantitative single-molecule imaging and genetics. The presentation will focus on the importance of eliminating ensemble averaging wherever possible and in the challenges of reconciling in vitro and in vivo experimental data and in building them into a mechanistic framework.
    Chair: Dr Paweł Zawadzki
    Seminar language: English
  150. /332/
    Date: Thursday 2017.09.14
    Speaker: Prof. Charles Henry Bennett
    Affiliation: IBM Fellow at IBM Research, Thomas J. Watson Research Center in Yorktown Heights, New York.
    Title: Is there such a thing as private information?
    Abstract: One of the original motivations for quantum information theory was the use of quantum effects to protect the privacy of classical communications. Yet the new theory, which has grown to elegantly encompass all of classical informatics, has undermined the very notion of classical private information, by showing that it sits on a slippery slope between quantum information and public information. Classical privacy survives only as a useful approximation, since in principle any memory so well shielded that it can hold classical data without the environment finding out can also hold superpositions of the classical values, thereby serving as a quantum memory. To recover a sharp notion of classical privacy it suffices to consider scenarios in which some information escapes to a place beyond the reach of one's adversaries.
    Biography: Prof. Bennett is one of the most acclaimed physicists and one of the founding fathers of modern quantum information theory. Among his many discoveries are: reversible computation, explanation of Maxwell's demon paradox, quantum cryptography, and quantum teleportation. He also created the foundations of entanglement theory and quantum communication. Prof. Bennett is a laureate of many awards including this year's Dirac Medal. See Wikipedia  for more details.
    Chair: Prof. Andrzej Grudka
    Seminar language: English
  151. /331/
    Date: Friday 2017.09.8
    Speaker: Dr Bernadeta Dobosz
    Affiliation: Zakład Fizyki Medycznej, Wydział Fizyki, UAM
    Title: Badanie metodą ESR fizycznych właściwości funkcjonalizowanych nanocząstek magnetytu jako potencjalnych nośników leków
    Abstract: Nanomateriały cieszą się coraz większą popularnością w różnych dziedzinach życia, również w medycynie. Na przykład nanocząstki magnetyczne stosuje się w obrazowaniu MRI czy w hipertermii. Szczególnie obiecujące jest ich wykorzystanie jako nośniki leków w terapiach celowanych. Dzięki właściwościom magnetycznym nanocząstek, stosując odpowiednie sekwencje pól magnetycznych, można kontrolować ich ruch. Funkcjonalizowane nanocząstki mogłyby dostarczać lek bezpośrednio do miejsca choroby (stan zapalny, guz) omijając tkanki zdrowe. Wspomniane wcześniej właściwości magnetyczne nanocząstek można badać metodą elektronowego rezonansu spinowego (ESR). Otrzymuje się w ten sposób wiele cennych informacji zarówno o rdzeniu magnetycznym nanocząstki jak i jej powierzchni. Właściwości nanocząstek zależą od wielu czynników takich jak pokrycie, dołączony materiał, środowisko czy warunki zewnętrzne, w których się znajdują. Wszystkie te zależności można badać metodą ESR. Stosując tę metodę można również kontrolować jakość nanocząstek oraz śledzić ich starzenie i agregację. Szczególne znaczenie pod kątem zastosowania nanocząstek w terapiach celowanych ma zastosowanie ESR do monitorowania dyfuzji nanocząstek wymuszonej obecnością pola magnetycznego.
    Chair: Prof. Maciej Krawczyk
    Seminar language: Polish
  152. /330/
    Date: Wednesday 2017.09.6
    Speaker: Dr Alexander Kvashnin
    Affiliation: Skolkovo Institute of Science and Technology, Moscow, Russia
    Title: Computational materials discovery in various dimensionalities
    Abstract: Computational materials discovery is a new field of science, and an ongoing scientific revolution. New methods have for the first time enable systematic discovery of superior materials on the computer – instead of the traditional laboratory-based trial-and-error approach. This approach allows scientists to predict and investigate new materials, new phenomena in various dimensionalities, starting from the bulk and moving towards the 2D materials, 1D materials and molecules, clusters. Here the recent research on the computational search for new functional materials will be discussed. Among the 2D materials, particular attention is drawn to such films of atomic thickness as graphene, its derivatives. In addition, many of non-carbon materials, which has no layered counterparts in bulk, are found to be layered graphitic-like in nanoscale. Such evidences related to silicon carbide, zinc oxide and aluminum nitride. In the field of bulk materials (single crystals, composites, etc.), the main direction of theoretical material science is search for crystal structure with optimal desired properties, such as hardness, band gap, dielectric constant, etc. Using the evolutionary algorithm implemented in the software package USPEX, it became possible to predict stable compounds, their crystal structure using only data on their chemical composition. In addition, we studied the surface reconstruction of rutile-like RuO2, especially the most stable (110) surface, which is highly important for catalysis, sensing and charge storage applications.
    Chair: Dr Piotr Graczyk
    Seminar language: English
  153. /329/
    Date: Wednesday 2017.06.21
    Speaker: Prof. Sergey Tarapov
    (Corresponding member of the National Academy of Sciences of Ukraine)
    Affiliation: Institute for Radiophysics and Electronics of the NAS of Ukraine, V. N. Karazin Kharkiv National University Kharkiv, Ukraine
    Title: Magnetic Metamaterials and Electron Magnetic Resonance at Microwaves: Experiment, Fundamental and Design
    Abstract: The results of experimental study of fundamental features of magnetically controlled metamaterials at microwave band are under discussion. Among them are: (1) the transformation of right-handed medium into left-handed medium and electrodynamic analogs of Tamm states; (2) the left-handed properties (controlled negative refraction) of semiconductor–ferrite composites; (3) formation of backward wave in the chiral magnetoactive medium; and (4) photonic crystals and magnetophotonic crystals. The possible technological implementations of metamaterials are described. Besides the special experimental equipment, designed for study both magnetic microwave metamaterials and electron spin/magnetic resonance in nanocomposites both at room and very low temperatures (0.3-300 K) are presented. Also the results of Electron Spin Resonance experimental research of spin dynamics in magnetic nanodots and nanostrips ensembles at T = 4.2-300K are discussed.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  154. /328/
    Date: Wednesday 2017.06.14
    Speaker: Prof. IF PAN dr hab. Tomasz Sowiński
    Affiliation: Institute of Physics of the Polish Academy of Sciences, Warsaw, Poland
    Title: Mass-imbalanced mixtures of several ultra-cold fermions in one-dimensional traps
    Abstract: With recent experiments on several particles confined in a one-dimensional optical traps quantum engineering has entered a completely new, so far unexplored, area of strongly correlated quantum systems. Apart from a few exceptions, it has commonly been assumed that particles of different kinds have the same mass and the main impact on properties of the system comes from an imbalance of the number of particles. In contrast, in my talk I will focus on the system of a few ultra-cold fermions of different masses. I will show that the mass difference between different fermionic components leads to the specific spatial fragmentation in one of the components. Although the mechanism predicted is universal with respect to the number of particles, the fragmentation occurs, depending on the shape of the confinement, for either the lighter or the heavier component. In consequence, the system may undergo a kind of critical transition that is induced by an adiabatic change of the external potential.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  155. /327/
    Date: Wednesday 2017.06.14
    Speaker: Dr Michał J. Michałowski
    Affiliation: Obserwatorium Astronomiczne, Wydział Fizyki, UAM
    Title: Dust in the distant Universe
    Abstract: I will summarize what we have learned about dusty galaxies at large distances from Earth. The characterization of their properties is crucial to understand the evolution of the Universe, because dust absorbed and re-emitted in the infrared 50% of stellar emission ever produced in the Universe. First, I will show my effort in obtaining the largest so far ( 2000 objects) sample of galaxies selected by their infrared emission. I will discuss their redshifts, stelar masses and star formation rates. These properties provide important tests of cosmological models. Then I will show how we can learn in what way the large masses of dust in the distant Universe were produced: either by asymptotic giant branch stars, by supernovae, or by dust grain growth in the interstellar medium. The knowledge of how early galaxies could produce their dust is important from the point of view of further evolution, because dust is enabling formation of molecular gas, the fuel for star formation.
    Chair: Prof. Maciej Krawczyk
    Seminar language: Polish
  156. /326/
    Data: Piątek, 9 czerwca 2017
    Prelegent: Dr Jędrzej Kociński
    Afiliacja: Zakład Akustyki Pomieszczeń i Psychoakustyki, WF UAM
    Tytuł: Testy zrozumiałości mowy jako uniwersalne narzędzie do badania zmysłu słuchu oraz wybranych układów fizycznych
    Streszczenie: Ocena zrozumiałości mowy jest nie tylko narzędziem diagnostycznym wykorzystywanym w protetyce słuchu, ale może dostarczyć wielu istotnych informacji na temat funkcjonowania układu słuchowego człowieka, a także może być wykorzystana w badaniach innych procesów w centralnym układzie słuchowym. Co więcej, metody oceny zrozumiałości mowy posłużyć mogą także do analizy funkcjonowania układów fizycznych począwszy od aparatów słuchowych poprzez pomieszczenia, na różnego typu algorytmach przetwarzania sygnałów skończywszy.

    Przedstawione do oceny publikacje wskazują na uniwersalność badań wykorzystujących zrozumiałość mowy w ocenie funkcjonowania zarówno układu słuchowego, jak i centralnego układu nerwowego. Co więcej prace te potwierdzają istotność, a wręcz konieczność wykorzystywania testów zrozumiałości mowy do oceny innych układów, w których ta zrozumiałość gra istotną rolę, jak np. algorytmy separujące sygnały, czy pętle indukcyjne wykorzystywane do poprawy zrozumiałości mowy u użytkowników aparatów słuchowych. Testy te posłużyć mogą także do weryfikacji obiektywnych parametrów służących jako predyktory zrozumiałości mowy (np. Speech Transmission Index, STI) lub jej poprawy (np. poprawa stosunku sygnału do szumu, SNR). Warto podkreślić, że wyniki prac otrzymano stosując najnowsze i najdokładniejsze metody pomiaru zrozumiałości mowy wnosząc tym samym nowe dane zarówno pod względem jakościowym, jak i pod względem obszarów badawczych.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  157. /325/
    Date: Wednesday 2017.06.7 at 13:00
    Speaker: Prof. Oleksandr V. Dobrovolskiy
    Affiliation: Physics Department, V. N. Karazin Kharkiv National University, Ukraine, and
    Physikalisches Institut, Goethe University Frankfurt am Main, Germany
    Title: Focused electron beam-induced deposition of magnetic nanostructures
    Abstract: Focused electron beam induced deposition (FEBID) is a direct-write approach for the fabrication of 2D and 3D nanostructures in various materials research areas. These comprise superconductors, magnetic materials, multilayer structures, and various sensor applications. FEBID is based on the decomposition of organo-metallic precursor gas molecules which are injected into the chamber of a scanning electron microscope. The deposition of the material takes place at those points where the electron beam dwells for a longer time in accordance with a pre-defined pattern. A post-growth processing of FEBID structures allows one to modify their compositional, structural and magnetic properties. In this talk, a general introduction to the basics of FEBID will be given, with an outline of available FEBID materials. A particular focus will be on Co-based FEBID nanostructures and tuning their magnetic properties on the lateral mesoscale by an area-selective post-growth processing. Further, exemplary 3D FEBID nanostructures will be presented and the perspectives of their use in fluxonic, photonic, and magnonic metamaterials will be outlined.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  158. /324/
    Date: Friday 2017.06.2, 11:30
    Speaker: Prof. Ryszard Jankowiak
    Affiliation: Department of Chemistry and Department of Physics, Kansas State University, Manhattan, KS, USA
    Title: Excitonic structure and dynamics in various photosynthetic antenna protein complexes: hole-burning and modeling studies
    Abstract: [PDF]  Low temperature (high-resolution) hole-burning (HB) spectroscopy and modeling studies of various optical spectra of photosynthetic complexes provide new insight into excited state electronic structure and dynamics. The following complexes will be briefly discussed: 1) The CsmA– bacteriochlorophyll α complex from C. tepidum. In this case, in contrast to literature data, an alternative structure is proposed for the baseplate; 2) The FMO antenna complex from C. tepidum and its mutants. Using an experimentally determined shape for the spectral density for the lowest- energy state (Jph(ω)), simulated optical spectra are obtained from structure-based calculations for the FMO trimer. For higher energy pigments, the effect of a broader Jph(ω) shape with a different S factor and/or variable Γinh are also tested for comparison. I will demonstrate that in order to properly describe various low-temperature optical spectra, a downward uncorrelated excitation energy transfer (EET) between trimer subunits must to be taken into account. That is, after light induced coherences vanish within each monomer, uncorrelated EET between the lowest exciton levels of each monomer takes place due to static structural inhomogeneities in the trimer. The information gained provides new insight into disorder, excitonic structure, EET dynamics and mutation induced changes induced via site directed mutagenesis; and 3) The B800-850 LH2 antenna complex from Alc.vinosum, which exhibits an unusual spectral splitting of the B800 absorption band. Here, we propose that various protein conformations lead to either strong or weak hydrogen bonds between the protein and B800 pigments.
    Biography: Ryszard Jankowiak is a Distinguished Professor of Chemistry and Ancillary Distinguished Professor of Physics at Kansas State University, Manhattan, KS, USA. He is also affiliated with the Photosynthetic Antenna Research Center, Washington University, Saint Louis, MO. He has published over 230 papers in various areas of physical chemistry, toxicology, chemical carcinogenesis, physics, and biophysics. Currently he studies photosynthetic reaction centers and various antenna pigment complexes (including mutants) of green plants/algae and photosynthetic bacteria using solid-state low-temperature (laser-based) spectroscopies and theoretical modeling. Research Gate score: 43.2; over 5,340 citations. H INDEX 39. Contact phone numbers: +(785) 532- 6785 or +(785) 410-4163.
    Chair: Prof. UAM dr hab. Krzysztof Gibasiewicz
    Seminar language: English
  159. /323/
    Date: Thursday 2017.06.01
    Speaker: Prof. Hendrik Ohldag
    Affiliation: A Distinguished Lecturer of the IEEE Magnetics (2017), SLAC National Accelerator Laboratory, Menlo Park, California, USA
    Title: Ultrafast and Very Small: Discover Nanoscale Magnetism With Picosecond Time Resolution Using X-Rays
    Abstract: Today’s magnetic device technology is based on complex magnetic alloys or multilayers that are patterned at the nanoscale and operate at gigahertz frequencies. To better understand the behavior of such devices one needs an experimental approach that is capable of detecting magnetization with nanometer and picosecond sensitivity. In addition, since devices contain different magnetic elements, a technique is needed that provides element-specific information about not only ferromagnetic but antiferromagnetic materials as well. Synchrotron based X-ray microscopy provides exactly these capabilities because a synchrotron produces tunable and fully polarized X-rays with energies between several tens of electron volts up to tens of kiloelectron volts. The interaction of tunable X-rays with matter is element-specific, allowing us to separately address different elements in a device. The polarization dependence or dichroism of the X-ray interaction provides a path to measure a ferromagnetic moment and its orientation or determine the orientation of the spin axis in an antiferromagnet. The wavelength of X-rays is on the order of nanometers, which enables microscopy with nanometer spatial resolution. And finally, a synchrotron is a pulsed X-ray source, with a pulse length of tens of picoseconds, which enables us to study magnetization dynamics with a time resolution given by the X-ray pulse length in a pump-probe fashion. The goal of this talk is to present an introduction to the field and explain the capabilities of synchrotron based X-ray microscopy, which is becoming a tool available at every synchrotron, to a diverse audience. The general introduction will be followed by a set of examples, depending on the audience, that may include properties of magnetic materials in rocks and meteorites, magnetic inclusions in magnetic oxides, interfacial magnetism in magnetic multilayers, and dynamics of nanostructured devices due to field and current pulses and microwave excitations.
    More information at 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  160. /322/
    Date: Wednesday 2017.05.31 at 13:00
    Speaker: Prof. Richard J. Spontak
    Affiliation: Departments of Chemical Biomolecular Engineering and Materials Science Engineering North Carolina State University Raleigh NC 27695
    Title: Biomimicry with Block Copolymers: Directed Self-Assembly via Crystallization or Chemical Coordination
    Abstract: Spontaneous self-assembly of block copolymer (BCP) molecules in a block-selective solvent typically results in the formation of micelles possessing a classical spherical morphology. Inclusion of a crystallizable block in the copolymer promotes crystallization-driven self-assembly (CDSA), yielding anisotropic cylindrical micelles that can, after additional processing, possess a remarkably narrow length polydispersity. Anisotropic nanoparticles prepared from BCPs are of growing importance as building blocks for the creation of a wide range of synthetic hierarchical materials. However, the assembly of such structural units is generally limited to the use of amphiphilic interactions. In addition to CDSA to generate single cylindrical micelles, reversible coordination-driven hierarchical self-assembly can be used to produce micron-scale fibers and macroscopic films based on the association of low-polydispersity cylindrical BCP micelles. In this case, coordination of palladium metal centers to phosphine ligands immobilized within the soluble coronas of BCP micelles is observed to induce intermicellar crosslinking, affording stable linear fibers comprised of micelle subunits in a staggered arrangement. The mean length of the fibers can be readily varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibers aggregate upon drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a significantly longer length scale. A comparable hierarchical self-assembly strategy yields toroidal micelles that combine to form micron-scale superstructures. Addition of a crystallizable BCP to a solution of a toroid-forming BCP results in the formation of toroidal multimicelles, as well as single-layer hexagonal arrays of connected toroids. By controlling the ability of the BCPs to form hydrogen bonds through the introduction of hydroxyl groups on the crystallizable BCP and the accompanying level of solvophobic interactions, the BCPs can spontaneously self-assemble to form 3D periodic mesoporous superstructures. Studies such as these demonstrate that self-assembly of BCPs into discrete, non-spherical nanostructures can be scaled from the "ground-up" to yield materials with intriguing morphologies and potentially unique properties.
    Chair: Prof. Michał Banaszak
    Seminar language: English
  161. /321/
    Data: piątek 2017.05.26
    Prelegent: Dr Oskar Baksalary
    Afiliacja: Quantum Physics Division, Physics Faculty, AMU
    Tytuł: Rachunek macierzowy wobec zagadnień z zakresu fizyki - reprezentacje odwrotności Moore'a-Penrose'a
    Streszczenie: Pojęcie odwrotności Moore'a-Penrose'a macierzy odgrywa ważną rolę w rozmaitych dziedzinach nauki. Bodajże najlepiej znany przykład jego zastosowania dotyczy metody najmniejszych kwadratów wykorzystywanej w większości obszarów badań naukowych odwołujących się do metod matematycznych. Jednak przykłady zastosowań odwrotności Moore'a-Penrose'a obejmują także inne zagadnienia, z których wiele wywodzi się z fizyki. W trakcie seminarium przedstawione zostaną rezultaty odnoszące się do odwrotności Moore'a-Penrose'a rozmaitych funkcji macierzy ze szczególnym naciskiem położonym na alternatywne sposoby reprezentowania tego pojęcia. Wśród poruszonych zagadnień znajdą się odwrotności Moore'a-Penrose'a macierzy zmodyfikowanej macierzą rzędu 1, odwrotność core (i jej związki z odwrotnościami Moore'a-Penrose'a, Botta-Duffina i grupową), a także unitarnie niezmiennicze miary rozseparowania przestrzeni wektorowych. W obrębie zainteresowania będą przy tym klasy macierzy hermitowskich, idempotentnych i EP.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  162. /320/
    Date: Thursday 2017.05.25
    Speaker: Dr Su-Yong Lee
    Affiliation: School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Korea
    Title: Single-photon non-locality test using feasible measurement setups
    Abstract: We test non-locality of a single-particle under feasible measurements, such as on-off and homodyne detections along with displacement and squeezing operations. On-off detection exhibits the existence of intensity of light by its click event, and homodyne detection shows the information on the phase of light by measuring intensity difference. We find that a single-particle entangled state can violate the CHSH inequality up to 2.782 when all four measurements are squeezed-and-displaced on-off detections.
    Chair: Dr hab. Paweł Kurzyński
    Seminar language: English
  163. /319/
    Date: Wednesday 2017.05.17 at 13:00
    Speaker: Prof. dr Mustafa Serkan Soylu
    Affiliation: Department of Physics, University of Giresun, Turkey
    Title: An example of combined experimental-theoretical characterization of metal (Nickel (II)) complex with neutral ligand
    Abstract: [PDF]  The term of computational chemistry may be defined as the mathematical description and numerical computation of molecular structures. The term computational chemistry is generally used when a mathematical method is sufficiently well developed that it can be automated for implementation on a computer. Computational chemistry has become a useful way to investigate materials that are too difficult to find or too expensive to purchase. It also helps chemists make predictions before running the actual experiments so that they can be better prepared for making observations. It’s also useful ways to explain of spectroscopic results of molecular structures. The mathematical description of the molecular structures based on the Quantum mechanics rules. Because of the Quantum mechanics (QM) is the correct mathematical description of the behaviour of electrons and thus of molecular structures. In theory, QM can predict any property of an individual atom or molecule exactly. In practice, the QM equations have only been solved exactly for one electron systems. A myriad collection of methods has been developed for approximating the solution for multiple electron systems. These approximations can be very useful, but this requires an amount of sophistication on the part of the researcher to know when each approximation is valid and how accurate the results are likely to be. In my presentation, I intend to give you some information about a few examples of our work entitled “Combined experimental–theoretical characterization of chelidamate nickel complex with 4-methylpyrimidine”. A new chelidamate complex of nickel (II) ion was synthesized and characterized by single-crystal X-ray diffraction, UV–Vis and FT-IR spectroscopy. Theoretical calculations have been carried out by using Hartree–Fock (HF)/6-31G (d) and Density Functional Theory (DFT)/6-31+G (d). HOMO–LUMO energies, absorption wavelengths and excitation energy were computed by time dependent DFT (TD-DFT) method with polarizable continuum model. The observed FT-IR vibrational frequencies are analysed and compared with theoretically predicted vibrational frequencies.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  164. /318/
    Data: piątek 2017.05.12, 12:00
    Prelegent: Dr Aleksandra Trzaskowska
    Afiliacja: Zakład Fizyki Kryształów, WF UAM
    Tytuł: Dyspersja fal powierzchniowych w strukturach fononicznych badana metodą wysoko rozdzielczej spektroskopii Brillouina
    Streszczenie: Przedstawiono wyniki badania wysokorozdzielczą spektroskopią Brillouina dyspersji fal powierzchniowych w różnego typu kryształach fononicznych. Powierzchniowe własności sprężyste badanych próbek symulowano, w każdym przypadku, metodą elementów skończonych (FEM). Dla jednowymiarowych kryształów fononicznych pokazano wpływ periodyczności sieci na amplitudę fal powierzchniowych. W przypadku kryształów dwuwymiarowych zaobserwowano istnienie przerwy energetycznej a w strukturach wyspowych wykazano także istnienie modów „oddychających". Ciekawe własności aplikacyjne obserwowano w przypadku zmodyfikowanej dwuwymiarowo struktury 1D.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  165. /317/
    Data: środa 2017.05.10 at 13:00
    Prelegenci: Mgr Justyna Łodyga i Prof. UAM dr hab. Andrzej Grudka
    Afiliacja: Quantum Electronics Division, Physics Faculty, AMU
    Tytuł: Zmarszczki czasoprzestrzeni, czyli fale grawitacyjne
    Streszczenie: 11 lutego 2016 roku międzynarodowy zespół naukowców poinformował o pierwszym w historii zarejestrowaniu fal grawitacyjnych. Fale te zostały zarejestrowane w Stanach Zjednoczonych równocześnie przez dwa detektory LIGO (Laser Interferometer Gravitational-wave Observatory), oddalone od siebie o ponad 3 tys. kilometrów.

    Podczas seminarium, w elementarny sposób omówimy różnice między teorią grawitacji Newtona a elektrodynamiką. Następnie przedstawimy w jaki sposób Einstein zmodyfikował teorię Newtona i omówimy podstawowe eksperymenty potwierdzające jego teorię grawitacji. Wyjaśnimy, dlaczego w teorii tej, podobnie jak w elektrodynamice, występują rozwiązania falowe. Na koniec omówimy wspomniany na początku eksperyment, w którym zaobserwowano fale grawitacyjne.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  166. /316/
    Data: środa 2017.05.10, 11:00
    Prelegent: Dr Krzysztof Cichy
    Afiliacja: Instytut Fizyki Teoretycznej, Uniwersytet Goethego we Frankfurcie, Niemcy
    oraz Zakład Fizyki Kwantowej, WF UAM
    Tytuł: Chromodynamika kwantowa na sieci z fermionami twisted mass
    Streszczenie: Chromodynamika kwantowa (QCD) jest obowiązującą teorią oddziaływania silnego. W reżimie niskoenergetycznym stała sprzężenia QCD jest duża i nie jest możliwe zastosowanie rachunku zaburzeń. Jedynym podejściem dającym ilościowe przewidywania z pierwszych zasad jest sformułowanie QCD na Euklidesowej sieci czasoprzestrzennej oraz obliczenie odpowiednich całek po trajektoriach numerycznie, używając algorytmów Monte Carlo. Seminarium to poświęcone będzie wynikom uzyskanym przy użyciu jednej z najważniejszych dyskretyzacji działania fermionowego, tzw. twisted mass. Przedstawimy wnioski dotyczące nieperturbacyjnej renormalizacji, a także spektralnych, chiralnych i topologicznych własności QCD.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  167. /315/
    Date: Wednesday 2017.04.26 at 13:00
    Speaker: Dr Ravindra Chhajlany
    Affiliation: Solid State Theory Division, Physics Faculty, AMU
    Title: Control of many body features in synthetic and real materials: selected topics
    Abstract: Rapid and major advances in the field of ultracold gases in optical lattices as well as ultra-fast pump-probe spectroscopy in solids are allowing unprecedented control of strongly correlated quantum many body systems with light. In this talk we shall present two examples of such control. In the optical lattice setting, we describe a new system that can be implemented in current state-of-the-art experiments with two species of fermions and tuned to extreme parameter regimes. This system exhibits a combination of interesting features: hidden string order, hole superconducting correlations and non-trivial excitations. In the condensed matter settings, we outline a recent experiment demonstrating the switching of orbitally ordered domains in the prototypical manganite LSMO (La0.5Sr1.5MnO4) with non-resonant THz light and provide a simplified model description of the observed effect.
    Chair: Prof. Adam Miranowicz Seminar language: English
  168. /314/
    Date: Wednesday 2017.04.12, 14:00
    Speaker: Dr Joanna Raczkowska
    Affiliation: Wydział Fizyki, Astronomii i Informatyki Stosowanej, Uniwersytet Jagielloński, Kraków
    Title: Innovative polymer coatings for controlled interactions with proteins and cells
    (Innowacyjne pokrycia polimerowe do kontroli oddziaływań z białkami i komórkami)
    Abstract: [PDF]  In recent years the growing attention is paid to a broad interdisciplinary 'bio-interface science', on the border between physics and biology, focused at the design of novel, innovative coatings enabling to use polymer materials with the controlled physicochemical properties for biomedical applications. The biocompatibility of the material and possibility of its biomedical applications is determined by its interactions with biological material, dependent on physicochemical properties of the surface, such as chemical composition, wettability, topography or elasticity. In the lecture, the idea of controlling the physicochemical properties of the substrate in the way enabling controlled interactions between the polymer coatings and the biological material will be presented. The results of performed experiments regarding the impact of substrate elasticity on the behavior of cancerous cells at different stage of cancer progression as well as the design and complex characterization of thermoresponsive, intelligent polymer coatings with controlled physicochemical properties will be reported. Conducted studies cover numerous steps, including the design and fabrication of polymer coatings with controlled properties, their complex characterization, as well as biocompatibility tests for both, proteins and cells. The obtained results enable deeper understanding of the complex interactions on the bio-interface between the surface and biological material.
    Streszczenie: W ostatnich latach jednym z głównych kierunków rozwoju nauk z pogranicza fizyki polimerów, biologii i medycyny jest poszukiwanie innowacyjnych rozwiązań pozwalających na wykorzystanie pokryć polimerowych o kontrolowanych właściwościach fizykochemicznych do zastosowań biomedycznych. O możliwościach aplikacyjnych podłoża decyduje jego zdolność do oddziaływania z materiałem biologicznym, determinowana przez właściwości powierzchni, takie jak skład chemiczny, zwilżalność, topografia czy elastyczność. W referacie zostanie przedstawione zagadnienie możliwości kontroli właściwości fizykochemicznych podłoża w celu uzyskania kontrolowanych oddziaływań pokryć polimerowych z białkami i komórkami. Opisane zostaną wyniki badań dotyczących wpływu elastyczności podłoża na zachowanie komórek nowotworowych o różnym stopniu zaawansowania oraz tworzenia i kompleksowej charakterystyki termoprzełączalnych inteligentnych pokryć polimerowych. Badania te obejmowały szereg etapów, poczynając od zaprojektowania i wytworzenie podłoży o zadanych właściwościach, poprzez kompleksową charakterystykę ich właściwości fizykochemicznych aż do testów biokompatybilności, prowadzonych zarówno dla białek, jak i dla komórek. Otrzymane wyniki pozwalają na głębsze poznanie skomplikowanych oddziaływań zachodzących pomiędzy podłożem a materiałem biologicznym.
    Chair: Prof. Maciej Krawczyk
    Seminar language: Polish
  169. /313/
    Date: Wednesday 2017.04.05, 14:00
    Speaker: Prof. Miroslav Holecek and mgr Milada Krejcova
    Affiliation: Faculty of Applied Sciences, Department of Mechanics, University of West Bohemia, Pilzno
    Title: Maxwell demon, Landauer principle, and stochastic processes focused on molecular motors
    Chair: dr hab. Przemysław Chełminiak
    Seminar language: English
  170. /312/
    Date: Wednesday 2017.04.05, 12:00
    Speaker: Dr Pavel Baláž
    Affiliation: Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Prague, Czech Republic
    Title: Magnetic properties of Bi2Se3 3D topological insulator doped by Mn atoms: theory and numerical simulations
    Abstract: Electric conductivity [1] and ferromagnetic Curie temperature of bulk Mn-doped Bi2Se3 and Bi2Te3 3D topological insulators are systematically studied by means of atomistic Monte Carlo simulations. Exchange interactions between the Mn magnetic moments have been calculated using ab initio methods. Tight-binding linear muffin-tin orbital method has been employed, together with the coherent potential approximation to describe the high degree of disorder in the system. Spin-orbit interaction is included in the ground state calculation. In the studied materials Mn atoms might either replace a Bi atom (substitutional position) or fill an empty position in van Der Waals gap between the atomic layers (substitutional position). It has been shown that exchange interaction between Mn magnetic moments might lead to a ferromagnetic phase transition. The Curie temperature is shown to be significantly dependent on the concentration of Mn atoms in substitutional and interstitial positions.
    [1] K. Carva, J. Kudrnovský, F. Máca, V. Drchal, I. Turek, P. Baláž, V. Tkáč, V. Holý, V. Sechovský, J. Honolka, Phys. Rev. B 93, 214409 (2016).
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  171. /311/
    Date: Friday 2017.03.31 at 13:00
    Speaker: M.Sc. Karam Chand
    Affiliation: University of New South Wales, Canberra Campus, Australia and Advanced Research Center, Saudi Aramco, Kingdom of Saudi Arabia.
    Title: Quantum channel capacity under realistic circumstances
    Abstract: Quantum channels can be used to transfer both classical and quantum information. The capacity of a quantum channel is defined by the upper bound of it transmission rate. The capacity improvement of a quantum channel remains an open question. In this presentation, I will discuss a systematic method to investigate quantum channel capacity in spectral domain under stringent constrained resources, particularly photons, which is then apportioned under more realistic circumstances. Here, a classical signal analysis methodology is used to match the power spectral density of the signal to the spectrum of a squeezed channel supported by a subthreshold optical parametric oscillator. Furthermore, using water-filling algorithm, I will define and declare the first time, the upper bound of the channel capacity of a quantum channel under realistic practical assumptions. Following on from that, I will establish the best signal-to-noise ratio and bit-error-rate that can be achieved for a bipolar non-return to zero digital signals imposed on the squeezed output of a sub-threshold optical parametric oscillator, for given fixed number of photons in the channel. For a range of parameters, I will establish the circumstances under which the squeezed channel can perform better than a classical channel (as supported by a coherent state). Using these techniques, I will optimize the capacity of a quantum channel for a given photon flux in the channel. This also provides the machinery needed to design experiments that would demonstrate quantum enhancement. Further discussion, if one considers mismatched parameter regime, in fact very importantly show how by increasing squeezing level decreases quantum enhancement. I will also discuss how to use these ranges of optimum parameters to design a quantum channel.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  172. /310/
    Date: Wednesday 2017.03.22, 12:00
    Speaker: Dr hab. Adam Sawicki
    Authors: Adam Sawicki and Katarzyna Karnas
    Affiliation: Center for Theoretical Physics of the Polish Academy of Sciences, Warsaw
    Title: Universal quantum gates
    Abstract: I will consider the problem of deciding if a finite set of quantum one-qudit gates is universal, i.e if the generated group is either the special unitary or the special orthogonal group. To every gate I will assign its image under the adjoint representation. The necessary condition for the universality is that the only matrices that commute with all the adjoint representation matrices are proportional to the identity. If in addition there is an element in the considered group whose Hilbert-Schmidt distance from the centre is smaller than 1/√2, then the set of gates is universal. Using these I will present a simple algorithm that allows deciding the universality of any set of d-dimensional gates in a finite number of steps. Moreover, I will formulate the general classification theorem. This is a joint work with Katarzyna Karnas.
    Chair: Prof. UAM dr hab. Andrzej Grudka
    Seminar language: English
  173. /309/
    Data: Środa 2017.03.22, 10:00
    Prelegent: Mgr Przemysław Sadowski
    Afiliacja: Instytut Informatyki Teoretycznej i Stosowanej PAN w Gliwicach
    Tytuł: Kwantowe wyszukiwanie z dodatkową wiedzą o sieci
    Streszczenie: Prezentowana praca jest poświęcona analizie modelu błądzenia kwantowego wzbogaconego o możliwość definiowania różnych rodzai krawędzi. Poszczególne rodzaje krawędzi definiowane są poprzez zróżnicowanie zmiany fazy następującej podczas przejścia daną ścieżką. Prezentujemy metody pozwalające lokalnie badać własności sieci oparte na rodzajach występujących krawędzi oraz sterować zachowaniem błądzenia w zależności od tych własności. W szczególności rozważamy problem przeszukiwania w przypadku gdy rodzaj krawędzi określa czy dany kierunek może prowadzić do szukanego wierzchołka.
    Prowadzący: Dr hab. Paweł Kurzyński
    Seminar language: Polish
  174. /308/
    Data: środa 2017.03.15, 12:00
    Prelegent: Dr Mikołaj Pochylski
    Afiliacja: Zakład Biofizyki Molekularnej, Wydział Fizyki, UAM
    Tytuł: Historia postępu w badaniach zjawiska rozpraszania Brillouina
    Streszczenie: Przewidziane blisko 100 lat, temu zjawisko rozpraszania Brillouina pozwoliło na połączenie dwóch wówczas niezależnych gałęzi fizyki: termodynamikę i optykę. Od tego czasu, systematyczny rozwój technik pomiarowych zamienił ciekawą koncepcję fizyczną w pełni rozwiniętą metodę spektroskopową wykorzystywaną w badaniach spontanicznych wzbudzeń akustycznych w materii skondensowanej.

    Podczas wystąpienia przedstawiona zostanie droga jaką przebyła metoda spektroskopii Brillouina, zaczynając od wyjaśnienia fizycznych podstaw zjawiska, które doprowadziły do jego teoretycznego przewidzenia. Zaprezentowany zostanie rozwój w konstrukcji wysoko-rozdzielczych spektrometrów optycznych, począwszy od pierwszych układów użytych do doświadczalnego potwierdzenia zjawiska rozpraszania Brillouina, aż po współczesne instrumenty wykorzystywane w fizykochemicznych badaniach materii skondensowanej. Omówiona zostanie również najnowsza konstrukcja spektrometru brillouinowskiego, dzięki której możliwy stał się szybki, bezkontaktowy i bezinwazyjny pomiar właściwości mechanicznych materii miękkiej, znajdujący zastosowanie w zagadnieniach biomedycznych.
    Prowadzący: Prof. Maciej Krawczyk
    Seminar language: Polish
  175. /307/
    Date: Friday 2017.03.10, 10.00
    Speaker: Prof. Michael Farle
    Affiliation: A Distinguished Lecturer of the IEEE Magnetics (2017), University of Duisburg-Essen, Germany, and Immanuel Kant Baltic Federal University, Russia
    Title: Functionalized Hybrid Nanomagnets: New Materials for Innovations in Energy Storage and Medical Theranostics
    Abstract: Imagine a future in which food is used to activate specific immune reactions in a human body based on an external noninvasive magnetic stimulus. Dream of a material that stores and releases energy reversibly by temperature changes between day and night. These visions may be realized by using magnetic nanoparticles that are functionalized to be biocompatible, environmentally stable and recyclable, self-healing, and low-cost.

    In this presentation I will discuss the basic concepts of magnetic nanomaterials and their magnetic properties with a focus on how to tune specific parameters in a controlled fashion to achieve the dreams of the future. I will highlight state-of-the-art experimental technologies that allow us to understand microscopic properties and interactions in relation to electronic structure changes caused by changes in size, shape, and composition of nanomaterials. Then I will discuss how this understanding is used when nanomagnets are functionalized for targeted drug delivery or composed to form macroscopic materials for new energetic applications like magnetic refrigeration. I will demonstrate that the seemingly complex behavior of hybrid metal/metal, metal/oxide, or oxide/oxide interface materials can be understood from the three fundamental interactions in magnetism: magnetic exchange interaction due to orbital overlap, spin-orbit interaction due to inner- and intra-atomic relativistic corrections (e.g., crystal field effects) and the long-range magnetic dipolar interaction. Several examples will be presented, including the formation of above-room-temperature ferromagnetic interface layers between low-temperature antiferromagnetic layers and the evolution of lattices of magnetic textures (skyrmions) in confined dimensions. The talk will end with an episode in the life of an imaginary golf-playing couple in the year 2040 who use their “Smart Magnet” (SMAG) phone to energize and heal their bodies on the green.
    Biography: Michael Farle received his Diploma in experimental physics, Doctorate, and Habilitation degrees from Freie Universität Berlin in 1984, 1989, and 1998, respectively. During this time he spent three and a half years as a senior researcher at Stanford University, California, and Université de Strasbourg, France. In 1999, he moved to Technische Universität Braunschweig, Germany, where he became a full professor. Since 2002, he has been working as a professor at the Universität Duisburg-Essen, Germany, where he has served as Vice-Rector for Research and Junior Scientific Staff. In 2016 he became, in addition, an adjunct professor at Immanuel Kant Baltic Federal University, Kaliningrad, Russia. Prof. Farle has published over 220 technical articles in peer-reviewed journals, including book chapters and review articles, and has given more than 60 invited presentations. He coordinated two European Research Networks and served as the vice-spokesman of Collaborative Research Center: Magnetic Heterostructures (SFB 491). Since 2014 he is chairman of the Magnetism Section of the German Physical Society. For many years he has been active on the program committees of several international conferences on magnetism. He is a member of the IEEE Magnetics Society, the German Physical Society, and is a co-editor of Materials Research Letters and Journal of Magnetism and Magnetic Materials. source: [IEEE Magnetics Society about the 2017 Distinguished Lecturer] 
    Chair: MK
    Seminar language: English
  176. /306/
    Data: środa 2017.03.01, 12:00
    Prelegenci: Mgr Filip Berski i Prof. UAM dr hab. Piotr Dybczyński
    Afiliacja: Obserwatorium Astronomiczne, Wydział Fizyki, UAM
    Tytuł: Bliskie przejścia gwiazd koło Słońca w świetle pierwszych wyników misji Gaia
    Streszczenie: Od roku 1950 kiedy to Jan H. Oort sformułował swoją hipotezę o sferycznym rezerwuarze komet otaczającym Układ Słoneczny trwają badania nad bliskimi przejściami gwiazdowymi. Oort sugerował, że takie zbliżenia są jedynym źródłem komet długookresowych (LPC's) – dziś wiemy, że działają również inne mechanizmy. Jednak częstość występowania bliskich przejść gwiazdowych jest wciąż tematem dyskusji. Wynika to między innymi z faktu, że do niedawna badania gwiazd zbliżających się do Słońca w głównej mierze opierały się na danych zgromadzonych przez sondę Hipparcos w pierwszej połowie lat 90. ubiegłego wieku, na podstawie których powstał katalog zawierający wszystkie parametry astrometryczne dla około 120 000. We wrześniu ubiegłego roku został opublikowany pierwszy katalog oparty o dane zgromadzone przez sondę Gaia z pierwszych 14 miesięcy jej działania. Katalog ten zawiera niezbędne informacje dla ponad dwóch milionów gwiazd. Jednym z pierwszych wyników uzyskanych dzięki temu katalogowi jest udokładnienie parametrów przejścia gwiazdy Gliese 710, która po tej korekcie przejdzie nie 60 tys. AU od Słońca jak to wynikało z wcześniejszych badań a tylko około 13 tys. AU. Tak bliskie przejście gwiazdy spowoduje duże perturbacje w Obłoku Oort'a czego skutkiem może być nawet dziesięć nowych komet rocznie pochodzących z tej odległej części Układu Słonecznego.
    Przewodnicząca seminarium: Prof. UAM dr hab. Agnieszka Kryszczyńska
    Seminar language: Polish
  177. /305/
    Date: Wednesday 2017.02.22, 12:00
    Speakers: Dr Michał Oszmaniec
    Affiliation: Acin's Group at the Institute of Photonic Sciences (ICFO) in Barcelona
    Title: Universal extensions of restricted classes of quantum operations
    Abstract: For numerous applications of quantum theory it is desirable to be able to apply arbitrary unitary operations on a given quantum system. However, in particular situations only a subset of unitary operations is easily accessible. This provokes the question of what additional unitary gates should be added to a given gate set in order to attain physical universality, i.e., to be able to perform arbitrary unitary transformation on the relevant Hilbert space. In this work, we study this problem for three paradigmatic cases of naturally occurring restricted gate sets: (A) particle-number preserving bosonic linear optics, (B) particle-number preserving fermionic linear optics, and (C) general (not necessarily particle-number preserving) fermionic linear optics. Tools from group theory and control theory allow to classify, in each of these scenarios, what sets of gates are generated, if an additional gate is added to the set of allowed transformations. This solves the universality problem completely for arbitrary number of particles and for arbitrary dimensions of the single-particle Hilbert space.
    After the presentation of these results, I will show they can be useful in the context of quantum metrology [1] and for the model of quantum computation based on fermionic linear optics [2,3].
    This talk is based on a joint project with Zoltan Zimboras (Freie Universitat Berlin).
    [1] M. Oszmaniec, R. Augusiak, C. Gogolin, J. Kołodyński, A. Acín, and M. Lewenstein, Phys. Rev. X 6, 041044 (2016)
    [2] Sergey Bravyi, Phys. Rev. A 73, 042313 (2006)
    [3] Fernando de Melo, Piotr Ćwikliński, Barbara M. Terhal, New J. Phys. 15 013015 (2013)
    Chair: Dr hab. Paweł Kurzyński
    Seminar language: English
  178. /304/
    Data: piątek 2017.01.27, 12:00
    Prelegenci: Dr Przemysław Bartczak i Mgr Grzegorz Dudziński
    Afiliacja: Obserwatorium Astronomiczne, Wydział Fizyki, UAM
    Tytuł: Rekonstrukcja kształtów planetoid z obserwacji radarowych
    Przewodnicząca seminarium: Prof. Agnieszka Kryszczyńska
    Seminar language: Polish
  179. /303/
    Date: Wednesday 2017.01.25, 12:00
    Speaker: Prof. Michał Banaszak
    Affiliation: High Pressure Physics Division, Physics Faculty, AMU
    Title: Artificial molecular machines revisited
    Abstract: The development and fabrication of mechanical devices powered by artificial molecular machines is one of the contemporary goals of nanoscience. Before this goal can be realized, however, we must learn how to control the coupling/uncoupling to the environment of individual switchable molecules, and also how to integrate these bistable molecules into organized, hierarchical assemblies that can perform significant work on their immediate environment at nano-, micro- and macroscopic levels. In this lecture we review some ideas for which the Nobel Prize in Chemistry was awarded in 2016.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  180. /302/
    Date: Wednesday 2017.01.18, 12:00
    Speaker: Prof. Piotr Tomczak
    Affiliation: Quantum Physics Division, Physics Faculty, AMU
    Title: Kosterlitz-Thouless transition in 1D Heisenberg antiferromagnet: An evidence based on topological properties of the ground state
    Abstract: A Kosterlitz-Thouless phase transition in the ground state of an antiferromagnetic spin-1/2 Heisenberg chain with nearest and next-nearest neighbor interactions is re-investigated from a new perspective: A mapping of the components of the scalar product onto loops is found. One can classify these loops according to whether any two of them can be transformed into each other in a continuous way (i.e., whether they have the same winding number). A finite size scaling of the fidelity susceptibility and geometrical phase calculated in the ground state of the considered system within each class of above mentioned loops leads to the critical value of coupling constant and critical exponents with high accuracy.
    Chair: Prof. Michał Banaszak
    Seminar language: Polish
  181. /301/
    Date: Friday 2017.01.13, 11:00
    Speaker: Prof. Tadeusz Domański
    Affiliation: Condensed Matter Theory Department, Marie Curie-Sklodowska University, Lublin
    Title: Majorana quasiparticles in nanoscopic superconductors
    Abstract: Recently there has been enormous interest in studying the Majorana fermions (identical with their own antiparticles) that can emerge as the effective quasiparticles in topological superconductors. They are appealing for the basic science and their non-Abelian character makes them promising for a brand new Majorana spintronics. So far the most convincing evidence for such exotic Majorana quasiparticles has been provided by tunneling measurements using, the Rashba chains brought in a contact with the s-wave superconducting samples (such as Pb). Independent experiments by groups in Delft, Princeton, Basel and Berlin have clearly indicated enhancement of the zero-bias STM conductance. Further efforts for detecting the Majorana fermions rely on novel methods, e.g. selective equal-spin Andreev reflection (SESAR), Josephson spectroscopy, fractional quantum interference etc. I shall describe main theoretical concepts beyond the Majorana-type quasiparticles, which can be regarded as mutations of the Shiba states of spinfull impurities in bulk superconductors. Next, I will illustrate non-local nature of such quasiparticles, discuss their fractionality (in comparison to ordinary electrons) and prove that they are not completely immune to disorder (despite a wide-spread belief). I will also comment on novel projects, related to localization of Majorana quasiparticles on interfaces or quantum defects.
    Chair: Prof. Ireneusz Weymann
    Seminar language: English
  182. /300/
    Date: Wednesday 2017.01.11, 12:00
    Speaker: Prof. Jan Martinek
    Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, Poznan
    Title: Topological phase transitions and topological phases of matter – Nobel in Physics 2016
    Chair: Prof. Antoni Wójcik
    Seminar language: English
  183. /299/
    Date: Wednesday 2017.01.04, 12:00
    Speaker: Prof. Zbigniew Ficek
    Title: Beating the limit of Quantum Fluctuations
    Affiliation: National Centre for Applied Physics, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
    Abstract: All systems fluctuate and according to quantum physics fluctuations persist even if all sources of error have been eliminated. The fluctuations limit the sensitivity achieved by detectors for spectral resolution and hence they limit the accuracy to which measurements can be performed. Quantum physics imposes a limit on the fluctuations called the quantum limit of fluctuations. Fluctuations of all systems including light are subject to this limit, and it was long believed that this limit could not be suppressed. In the 1980s theoretical studies followed by experimental measurements showed that the quantum limit can be beaten using quantum technologies that employ quantum effects such as quantum interference, squeezing, and entanglement. In this talk I will review the efforts done by researchers in the field of quantum optics to search for methods to reduce or even completely suppress the undesirable effects resulting from the presence of quantum fluctuations. The talk is based on the content of a book, Z. Ficek and R. Tanaś, Quantum-Limit Spectroscopy, published by Springer in November 2016.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  184. /298/
    Date: Wednesday 2016.12.21, 12:00
    Speaker: Prof. R. Wojciechowski*, Dr hab. M. Wiesner#, Prof. A. Lehmann-Szweykowska*, and Prof. Michał Kurzyński*
    Affiliation: *Solid State Theory Division and #Crystals Physics Division, Faculty of Physics, AMU
    Title: Spontaneous and strain-mediated commensurate-incommensurate phase transformations in LiCsSO4 and similar materials
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  185. /297/
    Date: Wednesday 2016.12.14, 12:00
    Speaker: Prof. Oksana Gorobets
    Affiliation: National Technical University of Ukraine “KPI” Kiev, Ukraine
    Title: Nonlinear solutions of the Landau-Lifshitz equations in antiferromagnetic materials
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  186. /296/
    Date: Friday 2016.12.09, 11:30
    Speaker: Prof. Teruo Ono
    Affiliation: A Distinguished Lecturer of the IEEE Magnetics (2016), Kyoto University, Japan
    Title: Spin Dynamics in Inhomogeneously Magnetized Systems
    Abstract: Worldwide efforts are underway to create revolutionary and energy-efficient data storage technology such as magnetic random-access memory (MRAM). An understanding of spin dynamics in inhomogeneously magnetized systems is indispensable for further development of nanoscale magnetic memory. This lecture provides a clear picture of inhomogeneously magnetized systems, such as magnetic nanowires with domain walls and disks with magnetic vortices, and presents not only technological developments and key achievements but also the unsolved puzzles and challenges that stimulate researchers in the field. First, the basic concept of an inhomogeneously magnetized system is described by introducing a magnetic vortex structure in a magnetic disk. A magnetic domain wall in a magnetic nanowire is also provided as a typical example. The magnetic field-driven dynamics of these inhomogeneously magnetized systems are described to illustrate their uniqueness. Second, electric-current-induced dynamics of magnetic vortices and domain walls are described. One can flip the core magnetization in a magnetic vortex using electrical current excitation, and move a domain wall by current injection into a wire. The next part focuses on the applications of current-induced magnetization dynamics in devices. The basic operations of two kinds of magnetic memories—magnetic vortex core memory and magnetic domain wall memory—are demonstrated. The lecture describes not only the current understanding about inhomogeneously magnetized systems, but also unexpected features that have emerged. It concludes with prospects for future developments.

    Biography: Teruo Ono received the B.S., M.S., and D.Sc. degrees from Kyoto University in 1991, 1993, and 1996, respectively. After a one year stay as a postdoctoral associate at Kyoto University, he moved to Keio University where he became an assistant professor. In 2000, he moved to Osaka University where he became a lecturer and an associate professor. Since 2004, he has been working at Kyoto University, where he is now a professor. He has published over 280 technical articles in peer-reviewed journals, including book chapters and review articles, and has given more than 90 invited presentations at international conferences. He served as conference co-chair of the 8th International Symposium on Metallic Multilayers (MML) in 2013, and on the program committees of various international conferences on magnetism and spintronics. He is a member of the IEEE Magnetics Society and is an editor of the Japanese Journal of Applied Physics. source: [] 
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  187. /295/
    Date: Wednesday 2016.11.16 at 13:30
    Speaker: Prof. Sylwester Porowski
    Affiliation: Instytut Wysokich Ciśnień PAN w Warszawie
    Title: Azotek galu GaN - od kryształów do struktur kwantowych
    Abstract: W prognozach głównych trendów rozwoju technologicznego i cywilizacyjnego w XXI wieku przewiduje się, że azotek galu (GaN), który jest stosunkowo nowym półprzewodnikiem, może odegrać rolę porównywalną z tą, jaką odegrał krzem w drugiej połowie XX wieku i bez którego trudno by było wyobrazić sobie obecnie funkcjonowanie świata. Nagroda Nobla z fizyki w 2014 r. dla I. Akasaki, H. Amano i S. Nakamury za skonstruowanie z GaN wydajnej diody emitującej światło niebieskie (blue LED) potwierdza trafność tych trendów. Wynalazek Noblistów pozwolił na dramatyczne zwiększenie efektywności zamiany energii elektrycznej na światło, co według szacunków amerykańskiego Departamentu Energii już w 2030 doprowadzi do zmniejszenia zużycia energii na oświetlenie w USA prawie o połowę. Na świecie badania azotku galu rozwijają się niezwykle dynamicznie i wiadomo już, że rewolucja w oświetleniu spowodowana wynalazkiem Noblistów jest dopiero początkiem przyszłych zastosowań tego półprzewodnika. Dlaczego jednak sukces tego półprzewodnika przyszedł tak późno? Które z jego własności o tym zadecydowały? Czy jest podobny do innych półprzewodników AIIIBV, czy też jest w nim jakaś tajemnica, która przez ponad 40 lat była barierą w praktycznym jego wykorzystaniu? Jakie to były bariery i jak zostały przełamane? W Polsce badania w tych dziedzinach rozwijają się bardzo intensywnie. Badania naukowe w zakresie fizyki i technologii tego stosunkowo nowego półprzewodnika są już obecnie prowadzone w 11 instytucjach naukowych. Powstały dwie firmy Ammono S. A. i TopGaN Sp. z o.o. prowadzące produkcję doświadczalną monokrystalicznych podłoży GaN oraz laserów niebieskich. Polska należy do elitarnej grupy krajów posiadających kompletną technologię produkcji niebieskich laserów (Japonia, Niemcy, USA, Polska). W prezentacji omówione zostaną niektóre wyniki polskich badań w dziedzinie w dziedzinie GaN oraz szanse na ich praktyczne wykorzystanie.
    Chair: MK
    Seminar language: Polish
  188. /294/
    Date: Wednesday 2016.11.09, 12:00
    Speaker: Dr Michał Krupiński
    Affiliation: The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Department of Materials Science, Kraków
    Title: Large Area Antidot and Dot Arrays with Perpendicular Magnetic Anisotropy
    Abstract: Recently, there has been growing interest in the fabrication, characterization, and modeling of patterned magnetic thin films due to their potential applications in the field of magnetic storage, sensors, radio frequency components, information processing, and magnonic crystals. This specific interest is primarily due to the possibility of controlling the magnetic properties by introducing in ferromagnetic material artificial defects such as antidots, dots or nonmagnetic inclusions arranged in ordered or disordered arrays. In particular, the hysteresis properties of such systems can be easily tailored by shape, size, and distance between the nanostructures as well as by arrays order and their symmetry. The talk will focus on the magnetic properties and switching behavior of well-ordered magnetic antidot and dot arrays consisting of Co/Pd thin films. The patterning effect as well as the influence of period and size on domain shape and domain wall behaviour will be discussed. Magnetic transition from antidot to dot regime will be also analysed.
    Chair: dr hab. Jarosław Kłos
    Seminar language: English
  189. /293/
    Date: Tuesday 2016.11.08, 12:00
    Speaker: Dr Ra’anan I. Tobey
    Affiliation: Zernike Institute for Advanced Materials, University of Groningen, Netherlands
    Title: Transient Grating Spectroscopy in Magnetic Thin Films: Magnetoelastic Transients, Spin Wave Generation and Interference, and Driven Nonlinear Phenomena
    Abstract: Control of material properties is one of the driving forces in ultrafast optical sciences. The notion that light can influence intrinsic material parameters is founded on a wide range of experiments demonstrating optomagnetic control, light induced superconductivity, and the photo induced insulator to metal transition in a wide range of materials. A recent addition to the tool chest of control methodologies is the excitation of acoustic waves, and their affect on intrinsic materials properties; particularly the material magnetization via magnetostrictive effects. In this talk I will describe our recent efforts [1,2] to optically generate in-plane magnetoelastic waves in the test material nickel. Using a combination of the transient grating (TG) and Faraday techniques, we probe the magnetic dynamics of the intrinsically acoustic excitations. The dispersion characteristics of our excitations can be uniquely identified as arising from in-plane Rayleigh and longitudinal acoustic excitations while at particular values of applied external magnetic field, the acoustic excitation coherently couples to a k-vector tunable ferromagnetic resonance in the film. I will balance the talk between discussion of the experimental apparatus and its benefits as well as discussing the array of elastically actuated FMR, dipole-exchange spin waves, and nonlinearities that arise. I will also discuss open questions and potential collaborative work.

    [1] J. Janusonis et al., APL 106, 181601 (2015).
    [2] J. Janusonis et al., arXiv:1601.04350 (2016).
    Chair: dr hab. Jarosław Kłos
    Seminar language: English
  190. /292/
    Date: Friday 2016.11.04, 12:00
    Speaker: Mgr inż. Łukasz Pawela
    Affiliation: Institute of Theoretical and Applied Informatics, Polish Academy of Sciences
    Title: Asymptotic distances of random quantum states and random quantum channels
    Abstract: Properties of random mixed states of dimension N distributed uniformly with respect to the Hilbert-Schmidt measure are investigated. We show that for large N, due to the concentration of measure, the trace distance between two random states tends to a fixed number ~D=1/4+1/π, which yields the Helstrom bound on their distinguishability. To arrive at this result we apply free random calculus and derive the symmetrized Marchenko-Pastur distribution, which is shown to describe numerical data for the model of coupled quantum kicked tops. Asymptotic value for the root fidelity between two random states, √F=3/4, can serve as a universal reference value for further theoretical and experimental studies. Analogous results for quantum relative entropy and Chernoff quantity provide other bounds on the distinguishablity of both states in a multiple measurement setup due to the quantum Sanov theorem. We study also mean entropy of coherence of random pure and mixed states and entanglement of a generic mixed state of a bi-partite system. For quantum channels, we show that their level density is also described by the Marchenko-Pastur distribution. This allows us to deduce some properties of the diamond norm of large dimensional quantum channels.
    Chair: Prof. UAM dr hab. Andrzej Grudka
    Seminar language: English
  191. /291/
    Date: Wednesday 2016.10.26, 12:00
    Speaker: Dr hab. Katarzyna M. Rećko
    Affiliation: Faculty of Physics, University of Białystok
    Title: Magnetic structure and basic interactions of MFe4Al8 (M=Sc and U)
    Abstract: Physics of transition metals and physics of f-electron elements belong to permanently fascinating subject. The experimental and theoretical research groups are interested in the mechanisms of fundamental interactions between atoms, leading to the formation of a specific crystal structures, the conditions for the formation of magnetic moments in metals and basic interactions between magnetic moments in the conditions of metallic bonds. The importance of the symmetry as well as the nature of the magnetic interactions between even distant partners are discussed and illustrated by selected systems. The correlation between the alloy’s composition and their degree of order are taken into consideration. The aim of the research presented here was to uncover the specific mechanisms leading to frequently noncolinear and incommensurate magnetic ordering of the alloys based on metals with the typical weakly localized magnetic moments, i.e. the elements of so-called 3d block coupled through band electrons as for example in light Actinides – 5f. During the search of the mechanisms responsible for long-range magnetic ordering of intermetallic systems based on simple p– and d–electron metals, in which, after all there is no dominance of effects such as magnetocrystalline anisotropy, the main attention was devoted to the aspects of symmetry of periodic commensurate crystal structures as well as commensurate and incommensurate magnetic ones. For the sake of clarity, a brief overview of known mechanisms of direct, indirect and super- exchange interactions of the Fe atoms, which have in the neighborhood p, d or f–electrons is given together with the general review of elementary sources of anisotropy due to the components of the measured compounds. All of the presented papers concern the results of experiments performed with the use of non-polarized neutron beams in the scenario of elastic and coherent scattering. Analysis of data collected for high symmetry directions allow determination of the details of magnetic interactions of exchange constants derived within the Weiss' molecular field theory approximation of the crystal field or in the tensor resulting from a search of the exchange constants by Monte Carlo methods. Recent papers in this vein are trying to adopt the simplest models, namely the crystal field model in the conditions of the low recognition of the input anisotropy parameters of the commensurate UFe4Al8 and the distribution of magnetization in an incommensurate ScFe4Al8.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  192. /290/
    Date: Thursday 2016.10.20
    Speaker: Doc. Jan Soubusta
    Affiliation: Institute of Physics of Academy of Science of the Czech Republic, Joint Laboratory of Optics of PU and IP AS CR, Olomouc, Czech Republic
    Title: Study of nonlinear magneto-optical effects
    Abstract: Nonlinear crystals are typically used when interaction of different colors of light is requested. In classical optics these nonlinear phenomena are used for second-harmonic generation, sum-frequency generation, optical parametric amplification or many other effects. In quantum optics, dealing with optical interaction on the level of individual photons, the most prominent process is spontaneous parametric down-conversion (SPDC). Influence of magnetic field on these nonlinear processes was not thoroughly tested yet. This topic deserves intensive study both from theoretical and experimental point of view, because the magnetic field can decrease the symmetry of the nonlinear crystal and so it may allow to use new types of phase-matching conditions. We started to test the SPDC process in BBO crystals. BBO is a trigonal (3m) negative uniaxial material. Nonlinear magneto-optic tensor of this material is not known and we can hardly predict it. According to our first theoretical derivation the efficiency of the nonlinear processes has to oscillate when rotating the magnetic-field orientation.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  193. /289/
    Date: Thursday 2016.10.20
    Speaker: Dr Antonín Černoch
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Construction of highly versatile four-photon source
    Abstract: We have constructed a four-photon source for quantum information processing experiments. In comparison to others implementation our source generates two different photon pairs - entangled, separable or completely mixed in polarisation.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  194. /288/
    Date: Thursday 2016.10.20
    Speaker: Dr Karel Lemr
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacký University, Olomouc, Czech Republic
    Title: Experimental measurement of the collectibility of two-qubit states
    Abstract: The talk will discuss the measurement of collectibility entanglement witness on several two-qubit states. I will present our experimental setup, the measurement procedure and then compare obtained data with theoretical prediction.
    Chair: Prof. Adam Miranowicz
    Seminar language: English
  195. /287/
    Date: Wednesday 2016.10.19, 12:00
    Speakers: Prof. Michał Kurzyński & Dr Przemysław Chełminiak
    Affiliation: Solid State Theory Division, Physics Faculty, AMU
    Title: The very laws of dynamics do not determine organization of physical systems. What is information?
    Abstract: Self-organization in thermodynamics and quantum as well as classical mechanics is the result of spontaneous symmetry (ergodicity) breaking, i.e., a random choice in the past. Under specially tuned conditions, when the system reaches a critical dynamics, self-organization becomes hierarchical. The very self-organized criticality is possible only in open systems. We tested the hypothesis that the conformational transition networks of the natively disordered proteins have a self-organized critical structure. Using a formalism of the generalized fluctuation theorem, we shown that the biological molecular machines with such dynamics transduce not only energy but also organization, defined by the suitable physical variable. Like work and heat are changes in energy, information and entropy production/reduction are changes in this variable.
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  196. /286/
    Date: Friday 2016.10.14, 12:00
    Speaker: Dr hab. Jarosław S. Kłos
    Affiliation: Zakład Fizyki Komputerowej, WF UAM
    Title: Symulacje komputerowe dendrymerów neutralnych i naładowanych
    Abstract: Dendrymery są polimerami zbudowanymi z łańcuchów liniowych (spejserów) połączonych sukcesywnie, generacja po generacji, w regularną, hierarchiczną strukturę drzewiastą. W zależności od panujących w roztworze warunków makrocząsteczki te są neutralne bądź uzyskują ładunek elektryczny. Ze względu na specyficzną, rozgałęzioną architekturę szkieletu molekularnego dendrymerów, oddziaływania objętości wykluczonej i elektrostatyczne mają duży wpływ na ich własności konformacyjne. Na seminarium zostaną przedstawione wyniki badań nad pojedynczymi, neutralnymi i naładowanymi dendrymerami z giętkimi spejserami, które przeprowadzono za pomocą gruboziarnistych symulacji komputerowych metodą Monte Carlo. Symulacje te pozwoliły na analizę rozmiaru i struktury wewnętrznej dendrymerów w szerokim zakresie liczby generacji i długości spejserów. Dla dendrymerów obdarzonych ładunkiem wykonane obliczenia umożliwiły obserwację i jakościowy opis efektu ich „puchnięcia” w warunkach neutralnego i niskiego pH.
    Chair: Prof. Maciej Krawczyk
    Seminar language: Polish
  197. /285/
    Date: Friday 2016.10.14, 10:00
    Speaker: Dr hab. Arkadiusz Józefczak
    Affiliation: Zakład Akustyki Molekularnej, Instytut Akustyki, WF UAM
    Title: Magnetic nanoparticles for enhancing the effectiveness of ultrasonic hyperthermia
    Abstract: Ultrasonic hyperthermia is a method of cancer treatment in which tumors are exposed to an elevated cytotoxic temperature using ultrasound (US). In conventional ultrasonic hyperthermia, the ultrasound-induced heating in the tumor is achieved through the absorption of wave energy. However, to obtain appropriate temperature in reasonable time, high US intensities, which can have a negative impact on healthy tissues, are required. The effectiveness of US for medical purposes can be significantly improved by using the so-called sonosensitizers, which can enhance the thermal effect of US on the tissue by increasing US absorption. One possible candidate for such sonosensitizers are magnetic nanoparticles with mean sizes of 10-300 nm, which can be efficiently heated because of additional attenuation and scattering of US. Additionally, magnetic nanoparticles are able to produce heat in the alternating magnetic field (magnetic hyperthermia). The synergetic application of ultrasonic and magnetic hyperthermia can lead to a promising treatment modality. [A. Józefczak et al., App. Phys. Lett. 108, 263701 (2016)].
    Chair: Prof. Maciej Krawczyk
    Seminar language: English
  198. /284/
    Date: Wednesday 2016.10.12, 12:00
    Speaker: Dr hab. inż. Bartłomiej Salski
    Affiliation: Instytut Radioelektroniki i Technik Multimedialnych, Politechnika Warszawska
    Title: Novel understanding of resonant modes in YIG microwave filters – experiments and electrodynamic study
    Abstract: Numerical solutions of coupled Maxwell and Landau-Lifshitz-Gilbert equations for a magnetized yttrium iron garnet (YIG) sphere acting as a one-stage filter will be discussed. The filter will be analysed using finite-difference time-domain technique. Contrary to the state of the art, it will be shown that the maximum electromagnetic power transmission through the YIG filter occurs at the frequency of the magnetic plasmon resonance with the effective permeability of the gyromagnetic medium , and not at a ferromagnetic resonance frequency. Such a new understanding of the YIG filter operation, makes it one of the most commonly used single-negative plasmonic metamaterials. The frequency of maximum transmission is also found to weakly depend on the size of the YIG sphere. An analytic electromagnetic analysis of resonances in a YIG sphere is performed for circularly polarized electromagnetic fields.
    Chair: Prof. Maciej Krawczyk
  199. /283/
    Date: Friday 2016.10.07, 12:00
    Speaker: Dr hab. Krzysztof Gibasiewicz
    Affiliation: Molecular Biophysics Division, Physics Faculty, AMU
    Title: Energy and electron transfer in photosynthetic proteins - fundamental and applied studies
    Abstract: During the lecture I will briefly present the results of my and my group’s studies being conducted within the last six years. Most of them comes from the fundamental experimental studies performed using the optical spectroscopic techniques on photosynthetic proteins isolated from bacteria, algae, and plants. These studies contributed, among others to understanding the role of the protein dynamics in intraprotein electron transport. I will also present our attempts to use the photosynthetic proteins in solar cells.
    Chair: Prof. Maciej Krawczyk
  200. /282/
    Date: Friday 2016.10.07, 10:00
    Speaker: Dr hab. Paweł Kurzyński
    Affiliation: Quantum Electronics Division, Faculty of Physics, Adam Mickiewicz University and Centre for Quantum Technologies, National University of Singapore
    Title: Indistinguishability, strong correlations and their dynamics in the quantum world
    Abstract: Quantum particles exhibit peculiar correlations that cannot be described by classical theories. These correlations are responsible for various physical phenomena and they lie at the heart of modern information theory. Additional complex features of quantum correlations are manifested when the underlying particles are fundamentally indistinguishable and when their dynamics occurs in interacting and open systems. In this talk I will present my recent results on how to describe, detect and model the evolution of quantum correlations in various scenarios. I will also discuss my future research directions related to this topic.
    Chair: Prof. Maciej Krawczyk
  201. /281/
    Date: Wednesday 2016.10.05, 10:00
    Speaker: M.Sc. Justyna Łodyga
    Affiliation: Quantum Electronics Division, Physics Faculty, AMU
    Title: Measure-independent conditional uncertainty principle
    Abstract: The uncertainty principle, which states that certain sets of quantum-mechanical measurements have a minimal joint uncertainty, has many applications in quantum cryptography. But in such applications, it is important to consider the effect of a (sometimes adversarially controlled) memory that can be correlated with the system being measured. The information retained by such a memory can in fact diminish the uncertainty of measurements. Recently, different uncertainty relations in the presence of memory were formulated in terms of the von Neumann conditional entropy. However, the entropy is not the only measure that can be used to quantify conditional uncertainty. Here, we develop a general operational framework that formalizes the concept of conditional uncertainty in a measure-independent form. Our formalism is built around a mathematical relation that we call conditional majorization. We define and characterize conditional majorization and demonstrate the use of this framework by deriving measure-independent conditional uncertainty relation in a tripartite scenario. In particular, we provide a state-independent lower bound on the minimal joint uncertainty that two remote parties (Bob and Eve) have about the outcome of a given pair of measurements performed by a third remote party (Alice), conditioned on arbitrary measurements that Bob and Eve make on their own systems.
    Chair: Prof. Maciej Krawczyk
  202. /280/
    Date: Wednesday 2016.06.29, 12:00
    Speaker: Prof. Richard J. Spontak
    Affiliation: Department of Chemical & Biomolecular Engineering, and Materials Science & Engineering, North Carolina State University, Raleigh, U.S.A.
    Title: The Dawning of a New Age for Thermoplastic Elastomers as Functional Materials
    Abstract: With recent advances made in the design and development of multifunctional polymeric materials, elastomers derived from triblock copolymers are in a good position to meet contemporary materials challenges and explore new technological opportunities. In this spirit, we consider the versatility of thermoplastic elastomer (TPE) systems, which provide an attractive alternative to chemically cross-linked materials because of their ability to microphase-separate and form nanostructures connected by a physically cross-linked network capable of withstanding substantial deformation. We first consider the stimuli responsiveness of triblock copolymers in the presence of midblock-selective additives. Upon incorporation of a midblock-selective oligomer, the molecular network formed by such copolymers can be tunably swollen to yield highly elastic soft systems, which exhibit composition-tunable mechanical properties (including time-composition rheological equivalence), as well as remarkable electromechanical properties. The morphological features and mechanical properties of swollen TPE gel systems generated from commercial and model styrenic TPEs will be surveyed. These materials, subjected to electrical stimulation as electroelastomers (i.e., dielectric elastomers) between compliant electrodes, are shown to achieve actuation strains greater than 300% and electro­mechanical coupling efficiencies in excess of 90%. The electrostatic mechanism by which electroactuation proceeds, as well as comparisons with other materials, will be discussed. Unlike conventional dielectric elastomers composed of chemically cross-linked elastomers, these copolymer systems are easily processable and broadly tunable in terms of composition, concentration and molecular weight, and they exhibit little cyclic hysteresis. In the case of acrylic TPEs, electroactuation occurs without the need for mechanical prestrain (often required to thin specimens so that lower voltages can be used to achieve high fields). These same triblock copolymers can be designed in conjunction with liquid metals to yield ultrastretchable/flexible electronic wires and antennae capable of remaining conductive beyond 1000% strain, as well as with phase-change additives to impart high-fixity/recovery shape memory. Incorporation of a charged midblock permits addition of polar additives that can further extend the scientific and technological diversity of TPEs. Development of stimuli-responsive, hyperelastic and shape-recovering polymeric materials, such as those to be presented here, is critical for emerging applications such as (micro)robotics, microfluidics and various biomedical devices.
    Chair: Prof. Michał Banaszak
  203. /279/
    Date: Wednesday 2016.06.15, 12:00
    Speaker: Prof. Ireneusz Weymann
    Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
    Title: Andreev transport in hybrid quantum dots
    Abstract: We will discuss the transport properties of quantum dots coupled to superconducting and normal electrodes, focusing on the transport regime where the current flows due to Andreev reflection. In the case of weak coupling between the leads and the dot, we show that Andreev current exhibits a nontrivial dependence on the bias and gate voltages, which is also reflected in magnetoresistive properties of the device. Moreover, we predict a zero-bias anomaly of the Andreev differential conductance in the parallel configuration of leads’ magnetizations, which is associated with a nonequilibrium spin accumulation in the dot triggered by Andreev processes. On the other hand, in the case of strong coupling between the leads and the dot, we study the influence of electron pairing on the Kondo state and show that the emerging Kondo resonance can be significantly enhanced by increasing the coupling to superconducting lead.
    Chair: Prof. Adam Miranowicz
  204. /278/
    Date: Wednesday 2016.06.08, 12:00
    Speaker: Prof. Marek Cinal
    Affiliation: Institute of Physical Chemistry, Polish Academy of Science, Warsaw
    Title: Magnetic damping in metallic layered systems
    Abstract: Dynamic magnetic phenomena, such as magnetization switching by spin transfer torque and the current-induced motion of domain walls, are strongly affected by spin relaxation. The Landau-Lifshitz-Gilbert equation which describes magnetization dynamics and is used as the basis for micromagnetic simulations, accounts for spin relaxation by the inclusion of the phenomenological damping term. The microscopic origin of the Gilbert damping is the spin-orbit interaction which also plays the key role in other effects of high relevance to spintronic applications. The talk will present quantum mechanical calculations of the Gilbert damping constant in magnetic layered systems (ferromagnetic films, ferromagnet/nonmagnet bi-, tri-, and multilayers built of transition metals) within the torque-correlation model. It will be reported how the damping constant depends on the type of nonmagnetic layers and the geometric dimensions of the considered structures. The origin of such dependences, including nonlocal damping in magnetic trilayers, will be analyzed using the spatial decomposition of the damping constant. In particular, the conditions for the enhancement of the Gilbert damping will be discussed.
    Chair: Prof. Maciej Krawczyk
  205. /277/
    Date: Monday 2016.06.06, 12:00
    Speaker: Dr Felix Pollock
    Affiliation: School of Physics & Astronomy, Monash University, Australia
    Title: How often does nature forget? The characterisation and statistics of non-Markovian quantum processes
    Abstract: In all but the most trivial open quantum process, some amount information about a system's state will be `remembered' by its environment, influencing the system's future evolution. However, in practice, the assumption of environmental `forgetfulness' or Markovianity is almost always made. This is partly for practical reasons - until now there has been no unified framework to describe the most general non-Markovian quantum dynamics - but also remarkably, because the Markovian assumption appears to be valid in many cases. I will present a new scheme for operationally characterising non-Markovian quantum processes, which both gives a theoretical understanding of such processes and provides a recipe for reconstructing them experimentally. Moreover, this scheme yields a natural measure on the space of of all processes, which I will use to ask the question: how Markovian is nature on average?
    Chair: Prof. Adam Miranowicz
  206. /276/
    Date: Wednesday 2016.05.25, 12:00
    Speaker: M.Sc. Marcin Jarzyna
    Affiliation: Faculty of Physics, University of Warsaw
    Title: Superadditivity in classical communication from a quantum parameter estimation perspective
    Abstract: We point out a contrasting role the entanglement plays in communication and estimation scenarios. In the case of communication it brings benefits both at the detection and input stages, the facts known as output and input super-additvity respectively. On the other hand, in estimation it is only the entanglement of the input probes that enables performance enhancement and we do not observe output super-additivity. We identify a regime where a connection between concepts crucial to the two fields is demonstrated. This allows us to shed new light on the problem of super-additivity in communication.
    Chair: Prof. Adam Miranowicz
  207. /275/
    Date: Tuesday 2016.05.17, 12:00
    Speaker: Prof. Keith E. Gubbins
    Affiliation: Department of Chemical Biomolecular Engineering, North Carolina State University, Raleigh, U.S.A.
    Title: Confinement-induced high pressure phases in nanopores: Can the pressure be in the megabar range?
    Abstract: [PDF]  There is an abundance of anecdotal evidence that nanophases adsorbed within nanoporous materials can exhibit high pressures as a result of the confinement [1,2]. For example, phase changes and chemical reactions that only occur at high pressures in the bulk phase occur in the confined phase at bulk phase pressures that are orders of magnitude lower. The pressure in the pore is a second order tensor, and for simple pore geometries has both a normal pressure component (normal to the walls) and one or more tangential components (parallel to the walls). For simple fluids in pores that are up to a few nanometers in width, molecular simulations show that both the normal and tangential pressures can be locally very high (thousands or tens of thousands of bars) in the pore, even though the bulk phase in equilibrium with the pore is at a pressure of one bar or less. The cause of these high in-pore pressures will be discussed, and where possible comparison with experimental results will be made [3]. When the molecules in the confined nanophase react with each other chemically it may be possible to achieve even higher tangential pressures, in the megabar range. Evidence for this is provided by recent experiments on sulfur (an insulator at ambient conditions) in narrow single-walled carbon nanotubes, carried out by Kaneko and coworkers [4]. They find that the sulfur atoms within the pore covalently bond to form a one-dimensional phase that is metallic. In the bulk phase sulfur forms a metallic phase only at pressures above 95 GPa. In our recent molecular dynamics simulations of this system we find that the sulfur atoms are covalently bonded in the pore and that they experience tangential pressures in excess of 100 GPa as a result of the strong confinement [5].

    [1] Yun Long, Jeremy C. Palmer, Benoit Coasne, Małgorzata Śliwinska-Bartkowiak and Keith E. Gubbins, “Pressure enhancement in carbon nanopores: A major confinement effect”, Physical Chemistry Chemical Physics, 13, 17163-17170 (2011).
    [2] Yun Long, Jeremy C. Palmer, Benoit Coasne, Małgorzata Śliwinska-Bartkowiak, George Jackson, Erich A. Müller and Keith E. Gubbins, “On the Molecular Origin of High Pressure Effects in Nanoconfinement: Effects of Surface Chemistry and Roughness”, Journal of Chemical Physics, 139, 144701 (2013).
    [3] M. Śliwinska-Bartkowiak,H. Drozdowski, M. Kempinski, M. Jazdzewska, Y. Long, J.C. Palmer and K.E. Gubbins, „Structural Analysis of the Behavior of Water Adsorbed in Activated Carbon Fibers”, Physical Chemistry Chemical Physics, DOI: 10.1039/C2CP22111J (2012).
    [4] Y. Fujimori, A. Morelos-Gómez, Z. Zhu, et al., “Conducting Linear Chains of Sulphur Inside Carbon Nanotubes”, Nature Comm., 4, DOI 10.1038/ncomms3162 (2013).
    [5] K.E. Gubbins, C.A Addington and J.M. Mansell, to be published.
    Chair: Prof. Małgorzata Śliwińska-Bartkowiak
  208. /274/
    Date: Thursday 2016.05.12, 12:00
    Speaker: Dr Maria Rosário Correia
    Affiliation: Auxiliary Professor of Physics Department of University of Aveiro, Researcher at I3N Associated Laboratory-Aveiro, Departmental coordinator of Erasmus+ and Campus Europae
    Title: Raman Spectroscopy in the study of structural and optical properties of different semiconductor nanostructures
    Abstract: For desired applications, a deep knowledge of the materials optical properties should be thoroughly investigated to improve their efficiency and device development. The Raman spectroscopy has been proved to be a powerful nondestructive technique that enables the investigation of the structural, electronic and optical properties of semiconductors nanostructures. In this talk an overview of the fundamental theoretical aspects of Raman scattering in will be given. The potentialities of the technique on the characterization of different semiconductor structures, will discussed based on cases study. The effect of the strain and compositional effects on the optical phonons of semiconductors based alloys, doping effects on the polar optical phonons, resonant effects, and confined effects in nanostructures are highlighted.
    Chair: Prof. Krzysztof Grygiel
  209. /273/
    Date: Wednesday 2016.05.11, 12:00
    Speaker: Prof. Marcus Münzenberg
    Affiliation: Department of Physics, Ernst-Moritz-Arndt-University, Greifswald, Germany
    Title: Ultrafast dynamics of spins and spin currents: magnetic storage and spintronic THz emitter
    Abstract: [PDF]  Magnetization manipulation is an indispensable tool for both basic and applied research. I will discuss some of the knobs to tune dynamics at ultrafast time scales. The dynamics of the response depends on the energy transfer from the laser excited electrons to the spins within the first femtoseconds. This determines the speed of the ultrafast magnetization: if the electrons are driven to a strong excitation density, a second slower process is found. This slowdown is a signature of the intrinsic ferromagnetic electron correlations in a ferromagnet. One possibility of control is to shape the properties of the electronic system. A special material of interest for magnetic storage development is FePt. This material allows an interesting modification of its density of states: Pt alloying increases the magnetic anisotropy and reduces the number of states at the Fermi level making it “more noble”. Consequently, the electron temperature shoots to higher values above the Curie temperature, a precondition for all-optical writing [1,2]. On the other side due to the non-equilibrium electron distribution, also ultrafast currents are generated and contribute to the laser driven spin dynamics. Similarly, to shaping the density of states in the first example, adjacent layers of a noble metals like Pt, Au or transition metals like W, Ta, Ru can shape the THz spin currents and convert ultrafast laser-driven spin currents via the ultrafast spin-Hall effect into a charge current burst. This opens a way towards novel THz spintronic devices: optimizing thicknesses and layers, we can realize efficient metallic THz spintronic emitters of ultra-broadband terahertz radiation competing with state-of-art photo-conductive switches THz emitters used for airport security [3,4].

    [1] J. Mendil, P. C. Nieves, O. Chubykalo-Fesenko, J. Walowski, M. Münzenberg, T. Santos, S. Pisana, Sci. Rep. 4, 3980 (2014).
    [2] U. Atxitia, O. Chubykalo-Fesenko, J. Walowski, A. Mann, and M. Münzenberg, Phys. Rev. B 81, 174401 (2010).
    [3] T. Kampfrath, M. Battiato, P. Maldonado, G. Eilers, J. Nötzold, S. Mährlein, V. Zbarskyy, F. Freimuth, Y. Mokrousov, S. Blügel, M. Wolf, I. Radu, P. M. Oppeneer, M. Münzenberg, Nature Nanotech. 8, 256 (2013).
    [4] T. Seifert, et al. arXiv:1510.03729
    Chair: dr hab. Jarosław W. Kłos
  210. /272/
    Date: Wednesday 2016.05.04, 12:00
    Speaker: Dr Michał Mruczkiewicz
    Affiliation: Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava, Slovakia
    Title: Particular Properties of Spin Waves in Magnonic Crystals
    Abstract: In the presentation I will show the results of investigation on spin waves in periodic ferromagnetic structures (magnonic crystals). The patterning at nanoscale permits to alter the propagation of spin waves and modify their properties. The focus of study is put on the following topics related to spin waves properties: i) standing spin wave formation in magnonic crystals ii) metamaterial properties for electromagnetic waves propagating through magnonic crystal, iii) nonreciprocal dispersion of spin waves and iv) collective dynamical skyrmion excitations in the arrays of magnetic dots.
    Chair: Prof. Maciej Krawczyk
  211. /271/
    Date: Wednesday 2016.04.20, 10:00
    Speaker: Prof. Antoni Wójcik
    Affiliation: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
    Title: Klasyczne splątanie czyli poplątanie pojęć
    Abstract: Seminarium będzie kontynuacją zeszłorocznego seminarium profesora Ryszarda Tanasia, na którym zaprezentowane zostały wyniki dotyczące tzw. klasycznego splątania. Chciałbym przedstawić ujednolicony i uproszczony model kilku różnych eksperymentów (Phys. Rev. Lett. 88 (2002) 097902, Sci.Rep. 5 (2015) 9175, arxiv: 1406.3338, arxiv: 1511.02265, arxiv: 1511.08144), których wyniki autorzy interpretują w kategoriach nieklasycznych korelacji klasycznych obiektów. Prosty model pozwala na krytyczne odniesienie się do takich interpretacji i pozwala lepiej zrozumieć sens mierzonych parametrów.
    Chair: Prof. Adam Miranowicz
  212. /270/
    Date: Monday 2016.04.18, 12:00
    Speaker: Dr Maciej Bilicki
    Affiliation: Sterrewacht Leiden, Universiteit Leiden, Netherlands
    Title: Observational cosmology with the largest surveys of galaxies
    Abstract: One of the pillars of the standard cosmological model is the observed distribution of galaxies on the largest scales, from our cosmic neighbourhood to the farthest possible distances. I will shortly describe how our knowledge of this distribution is being gathered thanks to galaxy surveys, with a short historical summary as well as the current status and future prospects. I will also mention examples of cosmological information that can be derived from such data and finally I will present my own and my collaborators' work on such surveys, with an emphasis on data sets covering the full extragalactic sky.
    Chair: Dr Agata Karska
  213. /269/
    Date: Wednesday 2016.04.13, 12:00
    Speaker: Prof. Tomasz Stobiecki
    Affiliation: Katedra Elektroniki, Akademia Górniczo-Hutnicza w Krakowie
    Title: Nanourządzenia elektroniki spinowej: magnetyczne złącza tunelowe i spin-torque oscylatory
    (przegląd badań prowadzonych na AGH)
    Abstract: [PDF]  W referacie omówię wyniki badań prowadzonych w Katedrze Elektroniki AGH nad magnetycznymi złączami tunelowymi z anizotropią magnetyczną w płaszczyźnie i prostopadłą, zwracając szczególną uwagę na prąd krytyczny potrzebny do przełączenia magnetyzacji i stabilność termiczną złącza. Na przykładzie magnetorezystancyjnych nanoelementów (AMR, GMR i TMR), działających w oparciu o efekt diody spinowej przedyskutuję wzbudzenia jednorodnych modów FMR i fal spinowych.
    Chair: Prof. Maciej Krawczyk
  214. /268/
    Date: Wednesday 2016.04.6, 12:00
    Speaker: Prof. Andrzej Wawro
    Affiliation: Institute of Physics of the Polish Academy of Sciences, Warsaw
    Title: Cienkowarstwowe nanokropki magnetyczne indukowane strukturyzowanym podłożem
    Abstract: [PDF]  Wykorzystując samoorganizujący się wzrost wysp Au o rozmiarach kilkudziesięciu nanometrów na powierzchni warstwy Mo [1] oraz silną zależność anizotropii magnetycznej ultracienkiej warstwy Co od rodzaju bufora, na którym jest ona osadzana, wytworzono w systemie MBE (molecular beam epitaxy) układ epitaksjalnych kropek magnetycznych [2, 3]. Kropki stanowi ta część warstwy Co, która jest osadzona na powierzchni wysp Au. Są one otoczone matrycą – warstwą Co osadzoną bezpośrednio na powierzchni Mo, pomiędzy wyspami Au. W zależności od grubości warstwy Co kropki i matryca charakteryzują się różnymi wzajemnymi kierunkami namagnesowania. Szczególna uwaga poświęcona jest konfiguracji, w której kropki są namagnesowane prostopadle do płaszczyzny warstwy, a namagnesowanie matrycy leży w jej płaszczyźnie. Stan remanencyjny układu oraz procesy przemagnesowania kropek badane są przy pomocy techniki magnetooptycznej (PMOKE) oraz mikroskopii sił magnetycznych (MFM). Magnetyczny jednodomenowy charakter w dużym zakresie rozmiarów kropek wynika z wysokiej jakości ich struktury krystalicznej. Skorelowano wielkość pola przełączania magnetycznego kropek z ich rozmiarami. Przeprowadzono symulacje mikromagnetyczne ilustrujące procesy przemagnesowania kropek oraz profile namagnesowania [4]. Symulacje te wykonano dla rozmiarów i kształtów kropek obserwowanych w eksperymencie. Poddano również analizie wpływ wewnętrznej struktury kropek typu core/edge. Zaproponowano diagram fazowy stanów magnetycznych i mechanizmów przemagnesowania kropek w funkcji parametrów opisujących ich strukturę.

    [1] A. Wawro et al., Nanotechnology 21 (2010) 335606.
    [2] A. Wawro et al., Europhys. Lett. 89 (2010) 37003.
    [3] A. Wawro et al., Phys. Rev. B 83 (2011) 092405.
    [4] E. Milińska and A. Wawro, J. Appl. Phys. 116 (2014) 193905.
    Chair: Prof. Maciej Krawczyk
  215. /267/
    Date: Wednesday 2016.03.23, 12:00
    Speaker: Prof. Igor Lyubchanskii
    Affiliation: Donetsk Physical and Technical Institute of the National Academy of Sciences of Ukraine and Department of Physics and Technology, Donetsk National University
    Title: Cascading processes in the nonlinear diffraction of light by standing acoustic waves
    Abstract: The contribution of two types of cascading process to the nonlinear optical diffraction of electromagnetic waves from a standing acoustic wave in a GaAs crystal is theoretically studied. The first type of cascading process results from second-harmonic generation followed by linear acousto-optical diffraction, while the second type involves linear acousto-optical diffraction from the standing acoustic wave and subsequent sum-frequency generation. In contrast to the third, direct, nonlinear acousto-optical diffraction process we previously investigated, the photoelastic interaction between electromagnetic and acoustic waves is here linear. We establish the rules governing the cascading processes and show that in most cases the output signal simultaneously results from two or even three of the possible nonlinear diffraction mechanisms. However, we demonstrate that a careful choice of the incidence angles of the incoming electromagnetic waves, of the polarization combinations of the incoming and diffracted waves, and of the type of acoustic wave (longitudinal or transverse) makes it always possible to distinguish between the direct and either of the two cascading processes.
    Chair: Prof. Maciej Krawczyk
  216. /266/
    Date: Wednesday 2016.03.9, 12:00
    Speaker: Prof. Joanna Trylska
    Affiliation: Centre of New Technologies, University of Warsaw
    (Centrum Nowych Technologii Uniwersytetu Warszawskiego)
    Title: Molecular dynamics simulations of ribosomal RNA
    Abstract: RNA has a complicated tertiary architecture and its internal dynamics is often related to function. To investigate the flexibility of RNA molecules we apply molecular dynamics simulations using different approximations; from all-atom representation in explicit solvent to simplified coarse-grained models. I will present examples of applications of molecular dynamics simulations to ribosomal RNA and experiments to determine thermodynamics of various ribosomal RNA fragments.
    Chair: Prof. Michał Banaszak
  217. /265/
    Date: Thursday 2016.03.3, 16:00
    Venue: Seminar room in Nano-Bio-Med Centre
    Speaker: Prof. Kwong-Yu Chan
    Affiliation: Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong
    Title: Polyelectrolyte Threaded in Metal-Organic Framework: A Lattice Boltzmann Material?
    Abstract: A new concept of structuring fixed charges in the nanoscale for optimum ion exchange performance is introduced. Crystalline porous charge exchange materials such as zeolites are inflexible and are restricted to cation exchange. Polymer resins have irregular porous structures. Fixed charges hidden by hydrophobic forces are exposed only after swelling in aqueous immersion. Threading polyelectrolyte chains into metal organic frameworks (MOF) form a superior ion exchange material that possesses advantages of both ceramic and polymeric domains. We report two new composites of polyelectrolytes synthesized within a MOF structure [1, 2].
    Cation exchange function is provided by sodium poly(4-styrene sulfonate) threaded in MIL-101 denoted as NaPSS MIL-101.[1] It is synthesized directly with polymerization in situ of the MOF, as shown in Figure 1. The NaPSS MIL-101 polyelectrolyte threaded in MOF has high surface area of 1850 m2/g and a large specific volume 0.85 mL/g. Figure 2(a) compares the ion adsorption kinetics to commercial ion-exchange resin IR-120. Excellent selectivity based on charge is demonstrated when NaPSS MIL-101 is immersed into a solution of two organic dyes, as shown in Figure 2(b). The anionic Acid Blue 9 is excluded though it has significant van der Waals affinity to high surface porous materials.Another example of polyelectrolyte synthesized in MOF is demonstrated by anionic polyvinyl benzyl trimethylammonium hydroxide (PVBTAH) threaded in ZIF-8 (PVBTAH ZIF-8), with structure shown in Fig. 3 [2].
    The high porosity, high surface area, uniform and ordered structure of metal organic frameworks provide fast reversible ion transport in a rigid nanoporous structure. On the other hand polyelectrolyte chains have their charges well separated and organized by the MOF framework, with reversible and local flexibility for ion-exchange function, as illustrated in Figure 3. This is analogous to the Lattice-Boltzmann model of discretizing and localizing dynamics of polymeric chains over a grid.

    [1] Liang Gao, Chi-Ying Vanessa Li, and Kwong-Yu Chan, "Polystyrene Sulfonate threaded in MIL-101Cr(III): a Cationic Polyelectrolyte Synthesized Directly into a Metal-Organic Framework", Chem. Mater. DOI: 10.1021/cm504623r. Publication Date (Web): April 30, 2015.
    [2] L. Gao, C.Y. V. Li, K.Y. Chan, and Z.N. Chen, "Metal-Organic Framework Threaded with Aminated Polymer Formed in Situ for Fast and Reversible Ion Exchange", J. Am. Chem. Soc. 136 (2014) 7209-7212.
    Chair: Prof. Stefan Jurga
  218. /264/
    Date: Wednesday 2016.02.10, 12:00
    Speaker: Dr hab. Izabela Szafraniak-Wiza
    Affiliation: Institute of Materials Science and Engineering, Poznań University of Technology
    Title: Ferroelectric perovskites for modern electronics
    Abstract: Ferroelectric materials offer a wide range of useful properties such as spontaneous polarization, pyroelectric, piezoelectric, and electro-optic effects that can be applied in non-volatile memories, actuators, transducers, and thermal sensors. From technological point of view several important issues concerning applications of ferroelectrics (like size effects, one dimensional structures, lead-free materials, multiferroic bismuth ferrite) are important and will be presented in this talk. Perovskites and perovkite-like compounds are conventionally obtained by solid-state reactions or wet-chemistry. The methods are related to high production costs and have serious disadvantages. A much less expensive alternative to the chemistry-based techniques is a direct synthesis from respective oxides at room temperature via mechanically triggered chemical reaction. The room temperature synthesis lowers the fabrication costs, eliminates the undesirable losses of volatile elements and enables the control of chemical and stoichiometry composition. The method has been recently used to obtain nanocrystalline electroceramic materials of perovskite structure like BiFeO3, PZT, Ba(Ti,Ca)O3, Ba(Fe1/2Nb1/2)O3, Bi3TiNbO3. The influence of the mechanochemical synthesis or mechanical activation on the final properties of the nanopowders and/or ceramics (obtained from those powders) will been discussed.
    Chair: Prof. Maciej Krawczyk
  219. /263/
    Date: Friday 2016.01.29, 12:00
    Speaker: Prof. Jan Peřina Jr.
    Affiliation: Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Science of the Czech Republic, Olomouc, Czech Republic
    Title: Coherence and dimensionality of twin beams generated from depleted pump fields
    Abstract: Using the model of parametric interaction based on the spatio-spectral Schmidt modes and generalized parametric approximation, we analyze coherence and mode structure of ultra-intense twin beams generated in the regime with pump depletion. We show that the increase of spatial and spectral coherence with the increasing pump power observed for moderate powers is replaced by the decrease for the pump powers at which pump depletion occurs. This behavior of coherence is opposed to that exhibited by the number of spatio-spectral modes effectively constituting the twin beam. The conditions for maximal coherence are analyzed considering pump-beam parameters (spectral width, transverse radius). The existence of additional coherence maxima occurring at even higher pump powers is predicted and explained by the oscillatory evolution of the modes' populations. Comparison with the experimental results is discussed.
    Chair: Prof. Adam Miranowicz
  220. /262/
    Date: Wednesday 2016.01.27, 12:00
    Note: A short tutorial on "How to apply for ERC grants" will follow at 14:30.
    Speaker: Dr Stefan Gillessen
    Affiliation: Max-Planck-Institut für extraterrestrische Physik, Garching, Germany
    Title: The Galactic Center: A unique astrophysical laboratory
    Abstract: [PDF]  Located at 8kpc only, the Galactic Center allows studying a galactic nucleus in unparalleled detail. With the advent of high-resolution, near-infrared instrumentation in the last decade it became possible to follow individual stellar orbits around the radio source Sgr A* with orbital periods as short as 12 years. The orbits provide compelling evidence for the massive black hole paradigm. The next generation near-infrared instrument GRAVITY aims at interferometrically combining the light of the four telescopes of ESO's VLT. The higher resolution will allow monitoring stellar orbits with orbital periods of 1 year only, and the relativistic prograde periastron precession gets accessible. The astrometric accuracy of GRAVITY is of order of the event horizon size of Sgr A*. This means that we might have access to measuring the spin of Sgr A*. In the past few years the small gas cloud G2 has been approaching Sgr A*. We were able to follow the tidal evolution of G2 for a decade, beautifully showing how the object got stretched ever more and how it passed the point of closest approach in 2014. The cloud is a unique probe of Sgr A*'s atmosphere, and we have observational hints that gas passing so close to Sgr A* experiences a drag force.

    Recommended popular articles:
    Gas cloud in the galactic centre 
    ERC Starting Grant for Stefan Gillessen 
    Obiad czarnej dziury szybko się zbliża 
    Chair: Dr Agata Karska
  221. /261/
    Date: Wednesday 2016.01.13, 12:00
    Speaker: Dr Agata Karska
    Affiliation: Astronomical Observatory of AMU
    Title: Interstellar molecules: A key to understand how stars like our Sun form
    Abstract: Stars form continuously in the dense and cold molecular clouds in our Galaxy. At the earliest stages of their formation, the proto-stars are surrounded by large amounts of dust and gas which make them invisible in the optical light. The most useful are in fact far infrared wavelengths containing the maximum of the dust emission and the key molecular transitions. The latter are a powerful tool to investigate the physical conditions of the gas and thus the physical phenomena at play during the star formation. In my talk, I will present the state-of-the-art spectroscopy of star forming regions from the Herschel Space Telescope. I will show how the observations of interstellar molecules such as water and carbon monoxide help astronomers to understand the physics of essentially hidden stages of star formation.

    Popular articles in Polish:
    Na początku jest woda 
    Zanim zabłysną 
    Astronomka z Poznania asystuje przy narodzinach gwiazd 
    Chair: Prof. Maciej Krawczyk
  222. /260/
    Date: Friday 2016.01.8, 12:00
    Speaker: Dr Koji Maruyama
    Affiliation: Osaka City University, Osaka, and Waseda University, Tokyo, Japan
    Title: Hamiltonian identification under limited access with minimal pre-knowledge
    Abstract: In order to control a quantum system, we need the full information on its Hamiltonian. Yet, how can we know all the entries of a Hamiltonian matrix, especially when the system is large and our access is limited? The problem of Hamiltonian identification under limited access has recently been studied quite actively. Here, after reviewing our results, we ask a more ambitious question along the same lines; what if we don’t know anything about the system and we still attempt to estimate its Hamiltonian through a small gateway? We shall discuss how we can probe such an ‘untouchable’ system E through a small gateway system S, paying a close attention to the equivalence class induced by the limitedness of access. The insight obtained hereby would open up a possibility of controlling a large quantum system with only a few parameters.
    Chair: Prof. Adam Miranowicz
  223. /259/
    Date: Friday 2016.01.8, 10:00
    Speaker: Dr Koji Maruyama
    Affiliation: Osaka City University, Osaka, and Waseda University, Tokyo, Japan
    Title: Maxwell’s demon and the physics of information
    Abstract: The paradox of Maxwell’s demon is probably the most famous example, in which physics (particularly thermodynamics) and the concept of information are linked. The tricky point of this paradox is in the necessity of the quantitative consideration of information acquisition by measurement. The related argument strengthened our notion that information processing is physical, and formed a firm basis of the science of quantum information. We will review the history of the efforts to resolve the paradox, the final exorcism by Landauer and Bennett, as well as some interesting consequences of the 2nd law [1].

    [1] Koji Maruyama, Franco Nori, and Vlatko Vedral, Rev. Mod. Phys. 81, 1 (2009) .
    Chair: Prof. Adam Miranowicz
  224. /258/
    Date: Thursday 2016.01.7
    Speaker: Dr Koji Maruyama
    Affiliation: Wolfram Research, Japan
    Title: Introduction to Mathematica 10 - the wonderland of computer algebra system
    Abstract: Mathematica is a software that was originally developed for researchers in mathematics and physics. Since its first release 26 years ago, it has evolved so greatly that it can now be applied to virtually everything, such as data visualisation, image processing, financial engineering, machine learning, etc., to name a few. We will cover as many functions it has as possible to impress you, and will answer any questions.
    The Mathematica notebook of this presentation can be downloaded from 
  225. /257/
    Date: Thursday 2015.12.10, 12:00
    Speaker: Dr Joachim Gräfe
    Affiliation: Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany
    Title: Static and Dynamic X-Ray Microscopy for Magnetic Nanostructures
    Abstract: Magnetic nanostructures, that are patterned on the length scale of the dipole and exchange interaction, have gained significant scientific interest in the past years [1-6]. These nanostructures have great potential for technological applications in data processing and storage, and spintronics [1-6]. However, the measurement of their microscopic magnetisation behaviour is challenging. For this task we use a combination of fast MOKE based first-order reversal curve (FORC) measurements, that we recently developed [7], and x-ray microscopy with XMCD contrast at our own endstation MAXYMUS@BESSY. FORC allows the magnetic separation of individual magnetisation reversal processes without the need for high lateral resolution. X-ray microscopy on the other hand yields a detailed nanoscopic image of the magnetisation and allows the observation of magnetisation dynamics on a picosecond timescale. To showcase the capabilities of these two powerful methods an antidot lattice (ADL) based magnonic crystal is discussed, among others. FORC and static x-ray imaging provide a detailed insight into the very complex and orientation dependent magnetisation reversal processes of ADL samples. The full magnetisation reversal is achieved by a combination of several reversible and irreversible steps that could not have been distinguished by conventional magnetometry. Subsequently, the time resolution capabilities of x-ray microscopy are leveraged to directly observe the individual spin wave modes in the magnonic crystal in the range from 250 MHz up to 8 GHz. Finally, the understanding of the static and dynamic magnetisation behaviour of these magnonic crystals allows tuning the magnon propagation length within the ADL in a range from 0.5 to 15 µm, thus, realising a simple spin wave filter.

    [1] Lenk, B. et al.: Phys. Rep. 507 (2011), 107
    [2] Haiming, Y. et al.: Nat. Commun. 4 (2013), 2702
    [3] Heyderman, L. J. et al.: Phys. Rev. B 73 (2006), 214429
    [4] Schwarze, T.; Grundler, D.: Appl. Phys. Lett. 102 (2013), 22
    [5] Manzin, A.; Bottauscio, O.: J. Phys. D - Appl. Phys. 45 (2012), 095001
    [6] Haering, F. et al.: Nanotechnology 24 (2013), 055305
    [7] Gräfe, J. et al.: Rev. Sci. Instr. 85 (2014), 023901
    Chair: Prof. Maciej Krawczyk
  226. /256/
    Date: Wednesday 2015.12.9, 12:00
    Speaker: Prof. Oksana Gorobets
    Affiliations: Institute of Magnetism, National Academy of Sciences of Ukraine, Kiev, Ukraine
    and National Technical University of Ukraine. Kiev, Ukraine
    Title: Effects of magnetic field at metal-aqueous electrolyte interface
    Abstract: The seminar will be focused on the magneto-hydrodynamic stirring of electrolyte in the combined electric and magnetic fields. We will present the estimations of the order of magnitude of the gradient magnetic force, gradient paramagnetic force, Lorentz force and damping force acting on ions embedded in aqueous electrolytes. The focus will be given to influence of magnetic field on the effectively para- and diamagnetic products of electrochemical reactions and the effects of phase separation under inhomogeneous magnetic field and Earth gravitation will be discussed. We will discuss also the influence of stray magnetic field of the ferromagnetic electrodes on a deposit structure and electrokinetic effects under inhomogeneous magnetic field.
    Chair: Prof. Maciej Krawczyk
  227. /255/
    Date: Friday 2015.12.4, 12:00
    Speaker: Prof. Manfred Albrecht
    Affiliation: Institute of Physics, University of Augsburg, D-86159 Augsburg, Germany
    Title: Future concepts and materials for magnetic data storage
    Abstract: [PDF]  Due to the increasing demand in high-density recording media, magnetic thin films with high magnetic anisotropy are widely studied in order to overcome the superparamagnetic effect. To fulfill the requirements of thermal stability, hard magnetic alloys, i.e. FePt alloys in the L10 phase are promising candidates as storage layer. However, owing to the large magnetic anisotropy, the magnetic field required to reverse the magnetization of the media may become higher than the field provided by a conventional recording head. To solve this, so-called writeability issue, the concepts of exchange-coupled composite (ECC) media as well as bit patterned media based on L10 FePt [1] were suggested, which will be discussed in this presentation. Furthermore, ultrafast magnetization switching is at the heart of both modern information storage technology and fundamental science. In this regard, it was recently observed that ultra-fast magnetization reversal processes can be induced by circularly polarized laser pulses in amorphous ferrimagnetic GdFeCo alloy thin films [2]. This novel observation resulted in a broad range of exciting and challenging fundamental questions, and may enable new applications based on ultra-fast spintronics. An overview of our activities on all-optical switching in amorphous ferrimagnetic Tb-Fe alloy films [3-5] will be presented.

    [1] C. Brombacher, M. Grobis, J. Lee, J. Fidler, T. Eriksson, T. Werner, O. Hellwig, and M. Albrecht, Nanotechnology 23, 025301 (2012).
    [2] C. D. Stanciu, F. Hansteen, A. V. Kimel, A. Kirilyuk, A. Tsukamoto, A. Itoh, and Th. Rasing, Phys. Rev. Lett. 99, 047601 (2007).
    [3] A. Hassdenteufel, B. Hebler, C. Schubert, A. Liebig, M. Teich, M. Helm, M. Aeschlimann, M. Albrecht, and R. Bratschitsch, Advanced Materials 25, 3122 (2013).
    [4] C. Schubert, A. Hassdenteufel, P. Matthes, J. Schmidt, M. Helm, R. Bratschitsch, and M. Albrecht, Appl. Phys. Lett. 104, 082406 (2014).
    [5] A. Hassdenteufel, J. Schmidt, C. Schubert, B. Hebler, M. Helm, M. Albrecht, and R. Bratschitsch, Phys. Rev. B 91, 104431 (2015).
    Chair: Prof. Maciej Krawczyk
  228. /254/
    Date: Wednesday 2015.11.25, 12:00
    Speaker: Dr Andriy Serebryannikov
    Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
    Title: Hybrid propagation, scattering, reflection and absorption regimes in advanced photonic structures
    Abstract: The talk is dedicated to the hybrid propagation, scattering, reflection, and absorption regimes that can be obtained in the advanced but still simple photonic structures and their microwave prototypes. Various manifestations of the diffraction inspired asymmetric transmission, a general phenomenon arising when using linear, isotropic, passive materials together with spatial inversion symmetry breaking, will be considered in the different structures, which include photonic crystal gratings, gratings made of ultralow-index materials, gratings based on hole-array metamaterials, and thin metallic gratings with a single subwavelength hole. The basic scenarios of directional selectivity achievable with the aid of these structures and their possible applications will be discussed. Then, the attention will be paid to ultrathin chiral metamaterials based on the coupled arrays of subwavelength resonators, which enable efficient polarization conversion and relevant channel and direction selectivity. The next topics will include reflection-enhanced absorption in photonic crystals made of polar dielectrics, multiple slow waves in graded-index photonic crystals, invisibility obtainable using high-index shells, and surface plasmons in deep annular-hole arrays. Finally, the transmission-mode spatial (angular) filtering in regular photonic crystals will be discussed alongside the reflection-mode spatial filtering, blazing, and splitting in thin reflector-backed gratings.
    Chair: Prof. Maciej Krawczyk
  229. /253/
    Date: Wednesday 2015.10.28, 12:00
    Speaker: Dr Michał Studziński
    Affiliation: Uniwersytet Gdański, Krajowe Centrum Informatyki Kwantowej w Gdańsku
    Title: Group representation approach to universal quantum cloning machines
    Abstract: Quantum information cannot be copied perfectly, in contrast with information from the "classical world". In other words, one is not able to copy perfectly an arbitrary quantum state. In terms of monogamy, if one wants to prepare some number of copies of the initially unknown quantum state, fidelities of cloning cannot be all equal to 1, there is a trade-off. This basic feature is known as ’no-cloning theorem’ and was recognized by Wootters, Zurek and Dieks. But still there is possibility for imperfect cloning. Using group-theory formalism, we show that the allowed region for fidelities can be expressed in terms of overlaps of pure states with irreducible representations of the partially transposed permutation operators. Additionally, it is sufficient to take pure states with real coefficients only, which makes calculations simpler. To obtain the allowed region, we make a convex hull of possible ranges of fidelities related to a given irreducible representations.
    Chair: Prof. Andrzej Grudka
  230. /252/
    Date: Wednesday 2015.10.21, 12:00
    Speaker: Prof. Andrzej Grudka
    Affiliation: Quantum Electronics Division, Physics Faculty, AMU
    Title: Do black holes create polyamory?
    Abstract: Of course not, but if one believes that information cannot be destroyed in a theory of quantum gravity, then we run into apparent contradictions with quantum theory when we consider evaporating black holes. Namely that the no-cloning theorem or the principle of entanglement monogamy is violated. Here, we show that neither violation need hold, since, in arguing that black holes lead to cloning or non-monogamy, one needs to assume a tensor product structure between two points in space-time that could instead be viewed as causally connected. In the latter case, one is violating the semi-classical causal structure of space, which is a strictly weaker implication than cloning or non-monogamy. This is because both cloning and non-monogamy also lead to a breakdown of the semi-classical causal structure. We show that the lack of monogamy that can emerge in evaporating space times is one that is allowed in quantum mechanics, and is very naturally related to a lack of monogamy of correlations of outputs of measurements performed at subsequent instances of time of a single system. This is due to an interesting duality between temporal correlations and entanglement. A particular example of this is the Horowitz-Maldacena proposal, and we argue that it need not lead to cloning or violations of entanglement monogamy.
    Chair: dr Karol Bartkiewicz
  231. /251/
    Date: Wednesday 2015.10.14, 12:00
    Speaker: Dr Ronan Lefort
    Affiliation: Université de Rennes 1, France
    Title: Confinement-induced nano-segregation of amphiphilic binary liquids
    Abstract: Environment care has now become a global societal challenge, on which physics and chemistry can turn to be leading actors and innovation leaders, especially in the domains of energetic transition, green nanoscience or ecomaterials. As an example, a great attention has been recently paid to the control of volatile organic compounds (VOCs) in home and working environments. Breakthroughs in the captation of VOCs have been achieved thanks to the mastering of novel porous nanomaterials, able to selectively filter or coadsorp molecular species. However, several scientific locks remain, related to the intricate balance of amphiphilic interactions and hydrogen-bond structures responsible for the behaviour of gaseous or liquid mixtures in nanopores. The physical parameters governing the nanostructures and the molecular dynamics of complex binary liquids confined in porous solids remain essentially unknown. We present here a general view of a model molecular binary system made of a ternary alcohol and an aprotic liquid, confined inside nanoporous silicas or carbons. Through a global experimental approach, we detail how the subtle balance of hydrophilic or -phobic interactions with interfaces in a nanoporous solid can lead to surprising nanostructures in the binary, and strongly affect both the hydrogen bonds network and the molecular dynamics of the system. We tentatively propose general routes for controlling coadsorption and/or nanofiltration of these complex binaries by tailoring specific nanoporous interfaces.
    Chair: Dr hab. Jacek Kubicki
  232. /250/
    Date: Friday 2015.10.09, 10:00
    Speaker: Prof. Yuri Oganessian
    Affiliation: Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia
    Title: Discovery of Super Heavy Elements
    Abstract: One of the fundamental outcomes of the modern nuclear theory of is the prediction of the "stability islands" in the domain of the hypothetical super heavy elements. The enhanced stability has been expected for the deformed nuclei near Z=108 and N=162, yet much stronger effect has been predicted for heavier spherical nuclei close to the shells Z=114 and N=184. The talk is devoted to the experimental verification of these predictions – the synthesis and study of both the decay and chemical properties of the new elements.
        The synthesis of the heaviest nuclei with high neutron excess has been carried out in the fusion reactions of U and the isotopes of man-made elements: from Np up to Cf with the Ca-48 projectiles in 2000-2015. The decay properties of the 52 synthesized nuclei – the isotopes of elements 104-118 - obtained in 48Ca-induced reactions presents direct experimental evidence of the existence of the super heavy nuclei that considerably expand the Periodical Table of the chemical elements.
        Simultaneously in the chemical studies of elements 112-114 by methods of absorption gas chromatography the influence of the “relativistic effect” on the chemical properties of the super heavy elements was obtained for the first time. The possibilities of further theoretical and experimental investigations in close collaboration with many European and American laboratories connected with construction in Flerov Laboratory “Super Heavy Element Factory” are also discussed.
        In the talk are used the results obtained in FLNR (JINR, Dubna) in collaboration with LLNL, (Livermore, USA), ORNL (Oak-Ridge, USA), and Vanderbilt University (Nashville, USA), Texas A M University (College Station, USA) as well as GSI (Darmstadt, Germany), PSI (Villigen, Switzerland) and RIKEN (Tokyo, Japan).
    Dodatkowe informacje: Profesor Oganessian należy do liderów w skali światowej w dziedzinie wytwarzania i badania własności fizycznych i chemicznych super ciężkich pierwiastków. Super ciężkie jądra atomowe tych pierwiastków stanowią obiekt zaawansowanych badań teoretycznych i eksperymentalnych prowadzonych w najlepszych centrach badawczych - głównie w Dubnej, USA i Niemczech. Profesor jest świetnym wykładowcą potrafiącym z pasją przedstawiać najnowsze wyniki badań.
    Chair: Prof. Wojciech Nawrocik
  233. /249/
    Date: Wednesday 2015.10.7, 12:00
    Speaker: Dr Kenneth P. Mineart
    Affiliation: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, USA
    Title: Understanding and Controlling the Morphology of a Midblock-Sulfonated Block Ionomer
    Abstract: Block copolymers containing ionic pendant groups, or block ionomers, have become increasingly popular due to their potential application as fuel cell and water desalination membranes, as well as components in photovoltaic devices and polymeric actuators. Block ionomers hold promise in these applications because of their inherent ability to form separate ionic and nonpolar microdomains at nanoscale dimensions. Segregation of ionic and nonpolar segments enables simultaneous water, or ion, transport and mechanical robustness. This is especially true when ionic segments are located in the midblock of a multiblock copolymer. The ionic and nonpolar blocks are, however, highly incompatible, which can lead to long-term metastable morphologies. While thermal annealing is typically used to refine block copolymer self-assembly to equilibrium structures, most block ionomers have inaccessible glass transition temperatures, thereby making thermal annealing ineffective. The establishment of morphological control in block ionomers represents the main challenge preventing widespread use. Here, we explore a variety of nanostructures formed during solution casting and then investigate a facile means by which to equilibrate the morphological behavior of a midblock-sulfonated pentablock ionomer. A combination of transmission electron microscopy and tomography (TEM/T) and small-angle X-ray scattering (SAXS) are used to probe nanostructural features present in films produced from different casting strategies. Results indicate that solvent-templating of nano-features following solution casting is prominent, but that subsequent solvent vapor annealing can be effective in equilibrating the morphology. To the best of our knowledge, these results provide the first evidence of morphological control/refinement in a block ionomer of commercially relevant molecular weight.
    Chair: Prof. Adam Patkowski
  234. /248/
    Date: Tuesday 2015.09.08, 12:00
    Speaker: Dr Paweł Zawadzki
    Affiliation: Oxford University, UK
    Title: Mechanisms of bacterial chromosome repair and segregation studied by smFRET and Super-Resolution microscopy
    Abstract: The single-molecules techniques are revolutionizing our understanding of biological processes and molecular mechanisms used by individual protein machines. I will introduce smFRET method and show how it was used to “observe” multiple conformational changes within recombination complex, acting in late stages of bacterial chromosome segregation, directly showing how recombination is activated and regulated. On the other hand, the real challenge in biology is to observe how individual proteins perform their function within living cell. I will present super-resolution microscopy and the ways I explore it to understand how individual UvrA and UvrB initiate pathway of DNA repair. I will show how these novel biophysical methods are changing our understanding of DNA repair process.
    Chair: Prof. Jacek Gapiński
  235. /247/
    Date: Monday 2015.07.13, 12:00
    Speaker: Prof. Keith E. Gubbins
    Affiliation: Department of Chemical Biochemical Engineering, North Carolina State University, Raleigh, USA
    Title: Corresponding States Theory for Thin Adsorbed Films
    Chair: Prof. Małgorzata Śliwińska-Bartkowiak
  236. /246/
    Date: Friday 2015.07.3, 12:00
    Speaker: Dr Ken Onda
    Affiliation: Interactive Research Center of Science, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
    Title: Photoinduced Dynamics in Organic Solid Materials Studied by Time-resolved Infrared Vibrational Spectroscopy
    Abstract: Recently photoinduced dynamics in organic solid materials have attracted more attention in terms of not only the fundamental physics but also the application to low-cost photo-electronic devices. However, photoinduced processes in organic materials are more complicated than those in inorganic solid materials due to their flexible and soft structures [1]. Time-resolved infrared vibrational spectroscopy is one of the ideal tools for studying these dynamics because a vibrational peak is sensitive to both local charge and structure in an organic solid material. We applied this method to the photoinduced phase transition in organic crystals and found that the different dynamics of charge and structure accompanied by the phase transition [2-4]. We also studied the initial photoexcited processes in metal complexes including a spin crossover complex and found the state which has not observed by the other methods [5]. Moreover, we confirmed that the results obtained by time-resolved vibrational spectroscopy is in good agreement with those by more structure sensitive time-resolved method, that is, time-resolved electron diffraction [6].
    [1] K. Onda, et al. Acc. Chem. Res. 47, 3494 (2014).
    [2] Y. Matsubara, et al. J. Phys. Soc. Jpn. 80, 124711 (2011).
    [3] N. Fukazawa, et al. J. Phys. Chem. C 116, 5892 (2012).
    [4] N. Fukazawa, et al. J. Phys. Chem. C 117, 13187 (2013).
    [5] T. Mukuta, et al. Inorg. Chem. 53, 2481 (2014).
    [6] M. Gao, et al. Nature, 496, 343 (2013).
    Chair: Dr hab. Jacek Kubicki
  237. /245/
    Date: Wednesday 2015.06.24, 12:00
    Speaker: Dr Felix Pollock
    Affiliation: Monash University in Melbourne, Australia
    Title: What a biased two-level system can tell you about its environment
    Abstract: Quantum process tomography (QPT), the full experimental determination of a quantum process, is usually used for benchmarking known systems. Here, I show how, by applying a large, controllable external bias, QPT of a two-level probe system can be used to determine a great deal about an unknown environment – including properties of its state and spectrum. The protocol I will discuss relies on few assumptions and could thus be applied to many systems of experimental interest, such as Bose-Einstein condensates, superconducting circuits and atoms in optical cavities. Within this talk, I will also discuss how one can do tomography for processes with initial correlations and hence those which are non-Markovian.
    Chair: Dr Karol Bartkiewicz
  238. /244/
    Date: Wednesday 2015.06.10, 12:00
    Speaker: Dr Fabrice Herpin
    Affiliation: University of Bordeaux, France
    Title: Results from the Herschel Space Observatory mission
    Abstract: The mission of the ESA Herschel satellite was completed in April 2013 after quite 4 years of activity. However, the incredible results of this far-infrared space observatory continue to revolutionize our view of the Universe. In particular, our knowledge of our Galaxy, of the stars and of our solar system has made significant progress thanks to the work carried out with this telescope, especially by the european teams. The formation mechanisms and the evolution of stars, of a few solar masses or greater, have revealed themselves a little more precisely: thanks to Herschel images and spectroscopic observations we now have a more global view of the genesis of stars and of their chemistry. The first complete observations of the water molecule allowed us to estimate the very significant amounts of water that exist in any planetary system in formation, but also to address the crucial question of the origin of water (and therefore life) on our own Earth.
    Chair: Dr Agata Karska
  239. /243/
    Date: Tuesday 2015.06.02, 12:00
    Speaker: Prof. Ryszard Tanaś
    Title: Can Bell’s inequalities be violated with classical fields?
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
    Abstract: Recently a number of papers appeared in which the notion of "classical entanglement" and its role in optical processes has been discussed. There are some experimental results already published showing that "classical entanglement" is sufficient to violate Bell’s inequalities. This can have important implications for commonly accepted interpretation of some physical phenomena. The talk is aimed to present some of these, still controversial, results.
    Chair: Prof. Adam Miranowicz
  240. /242/
    Date: Tuesday 2015.05.26, 12:00
    Speaker: Prof. Nitash Balsara
    Position: Charles W. Tobias Chair in Electrochemistry
    Affiliation: Chemical and Biomolecular Engineering, University of California, Berkeley, USA and Lawrence Berkeley National Laboratory
    Title: Batteries and Biofuels in the Clean Energy Landscape
    Chair: Prof. Michał Banaszak
  241. /241/
    Date: Wednesday 2015.05.20, 12:00
    Speaker: Dr Mirosław Łabuz
    Affiliation: Wydział Matematyczno-Przyrodniczy, Katedra Fizyki Teoretycznej, Uniwersytet Rzeszowski
    Title: Internal parity symmetry and degeneracy of Bethe Ansatz strings in the isotropic heptagonal magnetic ring
    Abstract: The exact Bethe eigenfunctions for the heptagonal ring within the isotropic XXX model exhibit a doubly degenerated energy level in the three-deviation sector at the centre of the Brillouin zone. I will demonstrate an explicit construction of these eigenfunctions by use of algebraic Bethe Ansatz, and point out a relation of degeneracy to parity conservation, applied to the configuration of strings for these eigenfunctions. Namely, the internal structure of the eigenfunctions (the 2-string and the 1-string, with opposite quasimomenta) admits generation of two mutually orthogonal eigenfunctions due to the fact that the strings which differ by their length are distinguishable objects.
    Chair: Prof. Adam Miranowicz
  242. /240/
    Date: Wednesday 2015.05.13, 12:00
    Speaker: M.Sc. Tomasz Wasak
    Affiliation: Katedra Optyki Kwantowej i Fizyki Atomowej, Instytut Fizyki Teoretycznej Uniwersytetu Warszawskiego
    Title: Cauchy-Schwarz inequality and particle entanglement
    Abstract: The creation of ensembles of entangled particles triggered the studies of fundamental aspects of quantum mechanics. The ability to generate non-classical correlations between atoms opened the possibility for their practical applications in non-trivial ways, for example in quantum computation or ultra-precise metrology. However, before the implementation stage, we must first make sure that the entanglement is present in the system, which is often a difficult task.
    In this seminar I will present the experiments that were conducted to verify existence of non-classical correlations in ultracold atomic systems. Then I provide a simple and experimentally accessible criterion for particle entanglement in many-body systems. This is based on a violation of the Cauchy-Schwarz inequality for the second order correlation function. It applies to any system of identical bosons with either fixed or fluctuating number of particles, provided that there is no coherence between different number states.
    Chair: Prof. Adam Miranowicz
  243. /239/
    Date: Wednesday 2015.05.06, 12:00
    Speaker: Dr Paweł Jakubczyk
    Affiliation: Wydział Matematyczno-Przyrodniczy, Katedra Fizyki Teoretycznej, Uniwersytet Rzeszowski
    Title: Entanglement of magnons in the Heisenberg XXX chain
    Abstract: I will present very simple analytical formulas for calculation of multipartite and bipartite entanglement of one-magnon states in quantum spin systems. Regarding the multipartite entanglement I will present formulas for global entanglement and N-concurrence and show that they are mutually related. In the bipartite case, I will give formulas for I-concurrence and negativity, and show that they are also scalable. For one-magnon Schur-Weyl states I will show that the bipartite entanglement structure is completely coded in the corresponding Young tableau.
    Chair: Prof. Adam Miranowicz
  244. /238/
    Date: Wednesday 2015.04.29, 12:00
    Speaker: Prof. Piotr Śniady
    Affiliation: Faculty of Mathematics and Computer Science, AMU
    Title: Joys and sorrows of a quantum computer owner (Radości i smutki z posiadania komputera kwantowego)
    Abstract: Some problems (such as factorization of large numbers into a product of primes) which seem to be difficult for a classical computer turned out to be very simple for a quantum computer. Is it a general pattern or are there some problems which are too difficult even for quantum computers?
    Chair: Prof. Adam Miranowicz
  245. /237/
    Date: Tuesday 2015.04.21, 12:00
    Speaker: Prof. K. Guslienko
    Affiliation: Universidad Del Pais Vasco/ Euskal Herriko Unibertsitatea (UPV/EHU), San Sebastian, Spain
    Title: Collective vortex excitations in magnetostatically coupled dot clusters
    Abstract: Low frequency gyrotropic dynamics (100 MHz range) in arrays of the interacting magnetic vortex state dots are considered. The interdot dynamical magnetostatic interactions are accounted in the form of explicit multipole decompositions on the inverse dot center-to-center distance. Particular case of the dot clusters consisting of 3 or 4 laterally placed cylindrical ferromagnetic dots on a nonmagnetic substrate in the form of equilateral triangles or squares is calculated. The eigenfrequencies of collective magnetic vortex oscillations are calculated analytically and compared with recent experiments conducted on the clusters of permalloy dots.
    Chair: Prof. Maciej Krawczyk
  246. /236/
    Date: Tuesday 2015.04.14, 12:00
    Speaker: Dr V. Kruglyak
    Affiliation: University of Exeter, Exeter, UK
    Title: Towards graded-index magnonics: Steering spin waves in networks of magnonic waveguides
    Authors: C. S. Davies,1 A. Francis,1 A. V. Sadovnikov,2 S. V. Chertopalov,3 M. T. Bryan,4 S. V. Grishin,2 D. A. Allwood,4 S. A. Nikitov,2,5 Yu. P. Sharaevskii2, and V. V. Kruglyak1
    1School of Physics, University of Exeter, Stocker road, Exeter, EX4 4QL, United Kingdom
    2Laboratory "Metamaterials," Saratov State University, Saratov 410012, Russia
    3Donetsk National University, 24 Universitetskaya Street, Donetsk, 83001, Ukraine
    4Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom
    5Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Science, Moscow 125009, Russia
    Abstract: [PDF]  The spin-wave dispersion is inherently complex and anisotropic, depending on both several magnetic parameters of the magnonic medium and the angle between the spin-wave vector and effective magnetic field. We have used time-resolved scanning Kerr microscopy and micromagnetic simulations to study the propagation of spin waves across Permalloy and yttrium-iron-garnet (YIG) waveguides, arranged to form junction structures and biased asymmetrically. We demonstrate that the non-uniformity of the internal magnetic field and magnetization inherent to patterned magnetic structures can create a medium of graded refractive index for propagating magnetostatic waves and can be used to steer their propagation in magnonic architectures. The character of the non-uniformity can be tuned and potentially programmed using the applied magnetic field. Thus, our findings suggest a possibility of a novel reconfigurable computing and / or signal processing technology based on the principles of the graded-index magnonics. [PDF] 
    Chair: Prof. Maciej Krawczyk
  247. /235/
    Date: Tuesday 2015.03.31, 14:00
    Speaker: Prof. Dr Peter Laggner
    Affiliation: Director of the Nanosystem Solutions Bruker AXS, Karlsruhe, Germany
    Title: Advanced Laboratory SAXS Technology. Bruker Instrumentation and Applications
    Chair: Prof. Maciej Kozak
  248. /234/
    Date: Wednesday 2015.03.25, 10:00
    Speaker: Dr inż. Piotr Kuświk
    Affiliation: Zakład Cienkich Warstw, Instytut Fizyki Molekularnej PAN w Poznaniu
    Title: Magnetyczne układy cienkowarstwowe o lokalnie modyfikowanych właściwościach i ich zastosowania
    Abstract: Magnetyczne układy warstwowe i wytwarzane z nich nanostruktury są przedmiotem badań wielu laboratoriów. Zainteresowanie tymi układami wynika z licznych, już zrealizowanych oraz perspektywicznych, zastosowań. Dotyczą one głównie technologii informatycznych oraz różnego typu elementów spintronicznych. Szczególnie interesujące są takie układy warstwowe, w których lokalna modyfikacja właściwości magnetycznych w płaszczyźnie warstw prowadzi do uzyskania specyficznej struktury magnetycznej, której realizacja w układach jednorodnych nie jest możliwa.
    Omówionych zostanie kilka przykładów modyfikacji anizotropii lub oddziaływania w układach warstwowych wykazujących anizotropię prostopadłą (Au/Co/Au, Pt/Co/Pt). Zmiany anizotropii w płaszczyźnie struktur uzyskiwano poprzez wytwarzanie warstw z kontrolowanym gradientem grubości (warstwy klinowe) lub w wyniku bombardowania jonowego. Bombardowanie warstw Au/Co jonami He lub Ar przez maski utworzone z regularnej dwuwymiarowej sieci nanokulek polistyrenowych, pozwoliło wytworzyć jednorodną sieć sztucznych domen umieszczonych w matrycy o kontrolowanych właściwościach magnetycznych [1]. Takie struktury są interesujące ze względu na możliwość wykorzystania do zapisu informacji. Uzyskanie monotonicznych zmian anizotropii lub oddziaływania międzywarstwowego pozwala na realizację procesu przemagnesowania poprzez, kontrolowaną jednorodnym polem magnetycznym, propagację pojedynczej prostej ściany domenowej [2-3]. Taki kontrolowany ruch ściany domenowej znajduje szereg potencjalnych zastosowań np., jako sensory magnetooporowe [3] lub układy typu lab-on-a-chip wykorzystujące pole rozproszone nad ściana domenową do transportu funkcjonalizowanych cząstek magnetycznych.
    [1] P. Kuświk inni, Nanotechnology 22, 095302 (2011); Nanotechnology 23, 475303 (2012).
    [2] M. Urbaniak i inni, Phys. Rev. Lett. 105, 067202 (2010).
    [3] M. Matczak i inni, J. Appl. Phys. 114, 093911 (2013); Nanoscale Research Letters 9, 395, (2014); Appl. Phys. Lett. 100, 162402 (2012).
    Chair: Prof. Maciej Krawczyk
  249. /233/
    Date: Wednesday 2015.02.25, 12:00
    Speaker: Dr Anna Kowalewska-Kudłaszyk
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
    Title: Entanglement evolution in nonlinear quantum scissors systems
    Chair: Prof. Maciej Krawczyk
    Abstract: We deal with the models of nonlinear quantum oscillators, described by the Kerr-like nonlinearities. The oscillators can interact with each other and with external environment in various ways. Such models are usually associated with optical nonlinear couplers and discussed in the context of the properties of light they generate [1]. The Kerr-like models discussed here can be treated, under some conditions, as nonlinear quantum scissors, because of their ability to limit substantially the number of states which are essential in the system's dynamics [2,3]. Moreover, this mechanism leads to creation of 2-qubit, 2-qutrit or qutrit-qubit systems for the discussed models. We will present the necessary conditions for creation maximally or almost maximally entangled states within such systems. Additionally, we will present different types of disentanglement in amplitude and phase damping reservoirs. For the models considered here we can observe asymptotic entanglement decay, death or entanglement revival. The conditions for such behavior will be presented.
    [1] J. Perina Jr., J. Perina, Progr. in Opt. 41, 361, (2000).
    [2] W. Leoński and A. Kowalewska-Kudłaszyk, Progress in Optics, 56 131 (2011).
    [3] A. Kowalewska-Kudłaszyk and W. Leoński, JOSA B, 31, 1290 (2014).
  250. /232/
    Date: Wednesday 2015.02.11, 12:00
    Speaker: Dr Pavel Baláz
    Affiliation: Polish Academy of Sciences, Institute of Molecular Physics, Poznań, Poland
    and A. Mickiewicz University, Faculty of Physics, Division of Mesoscopic Physics, Poznań, Poland
    Title: Spin current assisted magnetization dynamics in exchange coupled magnetic layers
    Authors: Pavel Baláz and Józef Barnaś
    Abstract: It has been shown experimentally, that when two magnetic layers are separated by a thin nonmagnetic one there is an exchange (RKKY) coupling between the magnetic layers, which oscillates between ferromagnetic and antiferromagnetic types when thickness of the spacing layer is changed [1]. Exchange coupled magnetic layers have a vast range of applications in spintronics with number of advantages over single magnetic layers. In magnetic spin valves they are utilized not just like current polarizers with negligible stray field but also as composite free layers offering novel possibilities of manipulation with magnetic moments by means of spin transfer torque. Thus, in the talk, current-induced switching of composite free layers with antiferromagnetic interlayer coupling shall be reviewed [2]. On the other hand, spin waves in layered magnetic structures have been extensively studied, both experimentally and theoretically, in the 80-ties and 90-ties of the past century [3]. Very recently a possibility of spin current induced spin wave excitation in magnetic insulators have been demonstrated [4]. Therefore, in the second part of the talk, influence of spin pumping and spin current on the spin wave spectra of two exchange coupled ferromagnetic insulators shall be discussed.
    This work has been carried out within the Project NANOSPIN PSPB-045/2010 supported by a grant from Switzerland through the Swiss Contribution to the enlarged European Union.
    [1] S. S. P. Parkin, N. More, and K. P. Roche, Phys. Rev. Lett. 64, 2304 (1990).
    [2] P. Baláz, J. Barnaś, Phys. Rev. B 88, 014406 (2013).
    [3] M. Vohl, J. Barnaś, and P. Grünberg, Phys. Rev. B 39, 12003 (1989); J. Barnaś and P. Grünberg, J. Magn. Magn. Mater. 82, 186 (1989).
    [4] Y. Kajiwara et al., Nature 464, 262 (2010).
    Chair: Prof. Maciej Krawczyk
  251. /231/
    Date: Wednesday 2015.02.4, 12:00
    Speaker: Dr Olga Malinkiewicz
    Affiliation: Saule Technologies Sp. z o.o., Warszawa
    Title: Unique properties of halide perovskites
    Abstract: Hybrid organic-inorganic perovskites have been rediscovered recently as great absorbers in solar cells. In these materials the combination of organic and inorganic components leads to a material that is both low-cost, solution processable and an excellent, crystalline semiconductor. Particularly the solar cell efficiency, now close to 20%, has triggered a huge research activity on otherwise rather conventional devices. In this short talk I will try to answer what is the origin of the unique properties of halide perovskites?
    Dodatkowe informacje: Dr Olga Malinkiewicz zajmuje się badaniami nad fotoogniwami perowskitowymi, będącymi od dwóch lat najbardziej obiecującym materiałem do konstrukcji nowej generacji baterii słonecznych. Podczas swojego pobytu na Uniwersytecie w Walencji dr Malinkiewicz odniosła spektakularny sukces, opracowując nową metodę wytwarzania fotoogniw perowskitowych na elastycznym podłożu i w niskich temperaturach. Odkrycie to, szeroko komentowane w polskich mediach,  zostało opublikowane w zeszłym roku w czasopiśmie Nature Photonics,  a sama autorka uzyskała za nie wiele prestiżowych wyróżnień dla młodych naukowców. Po powrocie do Polski dr Olga Malinkiewicz założyła firmę Saule Technologies, której celem jest komercjalizacja elastycznych fotoogniw perowskitowych.
    Przyjazd dr Olgi Malinkiewicz do Poznania jest związany z planami współpracy z grupą zajmującą się badaniami fotowoltaicznymi na Wydziale Fizyki UAM. Dr Malinkiewicz poszukuje także młodych, zdolnych osób do prowadzenia badań nad wytwarzaniem fotoogniw perwoskitowych, dlatego w szczególny sposób zapraszamy na seminarium studentów oraz doktorantów z fizyki i chemii.
    Chair: Prof. Maciej Krawczyk
  252. /230/
    Date: Wednesday 2015.01.28, 12:00
    Speaker: Prof. Michał Kurzyński
    Affiliation: Solid State Theory Division, Physics Faculty, AMU
    Title: Do biological molecular machines act as Maxwell's demons?
    Authors: Michał Kurzyński and Przemysław Chełminiak
    Abstract: In the intention of its creator, Maxwell's demon was thought to be an intelligent being, able to perform work at the expense of the entropy reduction of a closed operating system. The perplexing notion of the demon's intelligence was formalized in terms of memory and information processing by Szilard and subsequent followers, who pointed out that, in order for the total system to obey the second law of thermodynamics, the entropy reduction should be compensated for by, at least, the same entropy increase, related to the demon's information gain on the operating system's state. A non-informational formulation of the problem was proposed by Smoluchowski and popularized by Feynman as the ratchet and pawl machine, which can operate only in agreement with the second law. A. F. Huxley and consequent followers adopted this way of thinking to suggest numerous thermal ratchet mechanisms for the protein molecular machines' action, but no entropy reduction takes place for these models. More general models of protein dynamics have been put forward with a number of intramolecular states organized in a network of stochastic transitions. Here, the computer model of such a network is investigated, displaying, like networks of the systems biology, a transition from the fractal organization on a small length-scale to the small-world organization on the large length-scale. This model, when allowing work performance in a variety of ways, obeys the generalized fluctuation theorem with entropy reduction and is able to explain a surprising observation to Yanagida and co-workers that the myosin II head can take several steps along the actin filament per ATP molecule hydrolysed. From a broader perspective, the supposition that (i) a similar mechanism of action is characteristic for most intrinsically disordered proteins and (ii) this is the reason for most protein machines to operate as dimers or higher organized structures could be of especial importance.
    Chair: Prof. Michał Banaszak
  253. /229/
    Date: Wednesday 2015.01.21, 12:00
    Speaker: M.Sc., Eng. Bartłomiej Streszewski
    Affiliation: Faculty of Nonferrous Metals, AGH University of Science and Technology in Kraków
    Title: Kinetics of gold nanoparticles formation in aqueous and microemulsion systems
    Abstract: This work presents the results of kinetic measurements of the Au(III) chloride complex ions reduction with hydrazine and of the gold nanoparticles formation in aqueous solution and in microemulsion system of H2O/CTAB/alcohol/hexane. The dynamics of the gold nanoparticles formation in aqueous solution was studied using UV-Vis spectrophotometry, DLS and TEM methods. Nucleation and autocatalytic growth rate constants were determined by using the modified Finke Watzky model. The TEM measurements and hydrodynamic radius time evolution have revealed that the nanoparticles are unstable and grow until they reach a submicron size. The growth is triggered by the autocatalytic reduction of Au(I) ions on the surface of the growing particle and aggregation followed by chemical reaction limited by the Ostwald repining. Stabilization of gold nanoparticles can be provided by conducting their synthesis in reverse micelles. During the synthesis micelles act as nanoreactors and soft templates for the growing particles. The influence of the molar ratios: w = nH2O:nCTAB and p = nalc:nCTAB of the Au(III) ion initial concentration and the presence of different alcohols (butanol, pentanol, hexanol or heptanol) as cosurfactants on the formation kinetics and the nanoparticle morphology were studied. The particles with the smallest polydispersity are formed at a low Au(III) ion concentration and at for low w parameter or in the presence of alcohols with longer hydrocarbon chain. The particle growth is limited by the diffusion of the monomers between the micelles, which can be caused by a low Au(III) ion occupancy per a single micelle and/or a slow intermicellar exchange rate.
    Chair: Prof. Michał Banaszak
  254. /228/
    Date: Wednesday 2015.01.14, 12:00
    Speaker: Prof. Ryszard Krzyminiewski
    Affiliation: Zakład Fizyki Medycznej UAM
    Title: Terapia protonowa
    Abstract: Przedstawiony zostanie wpływ promieniowania jonizującego na tkankę biologiczną i jego wykorzystanie w podstawowej radioterapii nowotworów. Omówione będą sposoby generowania strumienia protonów oraz zalety i wady zastosowania wiązki protonów w leczeniu nowotworów. Pokazane zostaną przykłady ośrodków medycznych w Szwajcarii, Niemczech i Polsce stosujących w praktyce klinicznej terapię protonową. Zaprezentowane zostaną własne wstępne wyniki badań wpływu wiązki protonowej na nanoleki stosowane w terapii nowotworów.
    Chair: Prof. Michał Banaszak
  255. /227/
    Date: Wednesday 2014.12.17, 12:00
    Speaker: Dr Jan Chwedeńczuk
    Affiliation: Katedra Optyki Kwantowej i Fizyki Atomowej, Instytut Fizyki Teoretycznej Uniwersytetu Warszawskiego
    Title: Interferometry with independently prepared Bose-Einstein condensates
    Abstract: Whenever the value of an unknown parameter θ is extracted from a series of experiments, the result is inevitably burdened by the uncertainty ∆θ. If the system, which is the subject of measurement consists of unentangled particles, this uncertainty is bounded by the shot-noise limit. To overcome this limitation, it is necessary to use a properly entangled state, which is usually prepared in a dedicated procedure. We show that quantum correlations arising from the indistinguishability of bosons are a sufficient resource for the sub-shot-noise interferometry. To this end, we consider an interferometer, which operates on two independently prepared Bose-Einstein condensates with fluctuating numbers of particles. We calculate the sensitivity obtained from the measurement of the number of atoms and compare it with the ultimate achievable bound. Our main conclusion is that even in presence of major atom number fluctuations, an interferometer operating on two independent condensates can give very high precision. These observations indicate a new possibility for an interferometer operating below the shot-noise limit.
  256. /226/
    Date: Wednesday 2014.12.10 at 13:00
    Speaker: M.Sc. Krzysztof Wójcik
    Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
    Title: Transport properties of T-shaped double quantum dots
    Abstract: In my presentation I will mention transport properties of two quantum dots, coupled to two leads in, so called, T-shaped configuration. This mean, that one of the dots is embedded between the leads, while the second is not directly coupled to the leads, but coupled to the first dot. We restrict ourselves to the linear response regime. Nevertheless, the physics of such a system is still very reach and includes the two-stage Kondo effect (the conductance is enhanced below the Kondo temperature, but becomes suppressed at even lower temperatures) and Fano-like interference effects, resulting in a sharp dip in the conductance vs. gate voltage dependence. Moreover, both effects are strongly influenced by the presence of magnetism: either in the form of magnetic field, or encapsulated in ferromagnetic leads. In particular, the second stage of the Kondo effect can be suppressed (that is, the usual Kondo effect restored), and a perfect spin polarization of the conductance can be obtained due to the spin-dependent Fano anti-resonance condition. I will explain these effects, with stress put on the case of ferromagnetic leads (results were obtained with I. Weymann, ZFMezo, UAM). To resolve properly all the many-body correlations, we employed the Numerical Renormalization Group method.
  257. /225/
    Date: Thursday 2014.11.27, 12:00
    Speaker: Dr Tomasz Paterek
    1. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanynag Technological University, Singapore
    2. Centre for Quantum Technologies, National University of Singapore
    Title: Physics research and studies at Singapore’s NTU
    Abstract: This talk will be devoted to physics research and facilities at Nanyang Technological University (NTU) in Singapore and stipends it offers to undergraduate students (internships) and PhD students. I hope this will be of interest to faculty members who would like to collaborate with Singapore's scientists as well as students who would like to pursue their postgraduate career at NTU.
    Chair: Prof. Antoni Wójcik
  258. /224/
    Date: Wednesday 2014.11.26, 12:00
    Speaker: Dr Tomasz Paterek
    1. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanynag Technological University, Singapore
    2. Centre for Quantum Technologies, National University of Singapore
    Title: Quantum biology
    Abstract: With growing evidence of quantum effects in more and more complex systems it becomes legitimate to ask if alive matter can be influenced or take advantage of quantum features. Such questions are studied in a newly emerging field of quantum biology. Two examples will be discussed in more detail where quantum coherence may play a role to speed up biologically relevant process (photosynthesis) or even enable it (magneto-reception). Finally, I will describe our planned experiments on insects and how they are related to quantum biology.
  259. /223/
    Date: Thursday 2014.10.23
    Speaker: Dr Jacek Gąsiorowski
    Affiliation: Semiconductor Physics, Technische Univeristät Chemnitz, 09107 Chemnitz, Germany
    Title: Organic semiconductors - from light harvesting to solar fuels
    Abstract: During the past two decades thin film photovoltaic cells based on solution processable organic semiconductors attracted much attention as possible cheap energy harvesting systems. They are envisaged as feasible alternative to conventional inorganic technologies. One great advantage of the organic photovoltaic is that their morphological and photophysical properties can be easily modified by tailoring the molecular structure. Therefore, a great effort is made for the synthesis and characterization of new organic materials, small molecules and polymers. Another big advantage of the organic semiconductors is their mechanical flexibility. Optimisation of the polymer molecules from the fundamental core of this push-pull polymer have since gone on to produce single junction organic photovoltaic device with power conversion efficiency of 9%. The rapid increase in the light harvesting efficiency was also followed by the approaches in using solar energy for application in chemical reduction. Here, a particularly interesting approach is to use solar energy for the chemical and electrochemical reduction of CO2 to hydrocarbons as well as for the artificial photosynthesis.
    Chair: Prof. Małgorzata Śliwińska-Bartkowiak
  260. /222/
    Date: Thursday 2014.10.23
    Speaker: Prof. Dr Georgeta Salvan
    Affiliation: Semiconductor Physics, Technische Univeristät Chemnitz, 09107 Chemnitz, Germany
    Title: Magneto-optical Kerr Effect Spectroscopy of Organic/Ferromagnetic Heterostructures
    Abstract: Phthalocyanines and porphyrins find nowadays a variety of applications from pigments to organic electronics and, more recently, spintronics. This diversity of application potential stems from the large flexibility of their molecular structure. We focus on the room temperature magneto-optical activity of phthalocyanines and porphyrins deposited on ferromagnetic substrates (Co, Ni, and LSMO) as model heterostructures for organic spintronics. The magnetic properties of the heterostructures are assessed by magneto-optical Kerr effect (MOKE) magnetometry. Variable angle spectroscopic ellipsometry (VASE) in combination with MOKE spectroscopy investigations are performed to extract the (magneto-) optical properties of the heterostructures. From the degree of anisotropy of the optical constants the molecular orientation can be determined. This allows to systematically investigate the influence of the substrate magnetization direction onto the molecular arrangement.
    Chair: Prof. Małgorzata Śliwińska-Bartkowiak
  261. /221/
    Date: Wednesday 2014.10.8, 12:00
    Speaker: M.Sc. Michał Mruczkiewicz
    Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
    Title: Particular Properties of Spin Waves in Magnonic Crystals: Negative Refractive Index, Nonreciprocity and Damping
    Abstract: I am presenting the results of investigation of spin wave properties in periodic ferromagnetic structures (one-dimensional magnonic crystals). The main attention of research was put on development of numerical methods and analysis of spin waves properties that are important for designing a functional device. Three subjects of spin waves properties were studied and they can be classified as: i) influence of damping on standing spin wave formation ii) metamaterial properties for electromagnetic waves propagating through magnonic crystal and iii) nonreciprocal dispersion of spin waves. In particular I have shown the analysis of the influence of the damping factor on the spectrum of ferromagnetic resonance, the influence of metallic overlayer on the damping, influence of structural parameters of magnonic crystals on the magnetic permeability function of metamaterial based on the crystal. I have also presented a detailed analysis of symmetry breaking of the dispersion relation of spin waves propagating in the ferromagnetic films in contact with metal. The numerical calculation were confronted with measured data, when available, and agreement between them was shown.
    Chair: Prof. Maciej Krawczyk
  262. /220/
    Date: Monday 2014.09.1
    Speaker: Dr Bartłomiej Graczykowski
    Affiliation: Phononic and Photonic Nanostructures Group, Catalan Institute of Nanotechnology and Nanoscience (ICN2), Campus de la UAB - Edifici ICN2, 08193-Bellaterra (Barcelona), Spain
    Title: Acoustic phonon propagation in Si membranes and nanostructures
    Abstract: Studies on the phonon engineering have been gaining importance in recent 20 yr. Previous research has shown that phonon dispersion relation can be significantly modified by means of phononic crystals (PnCs) [1-3], spatial confinement [4-5], or external stress field [6-7]. Phononic crystals are in general materials with one- (1D), two-, or three-dimensional periodicity in their elastic properties. PnCs exhibit the modification of the phonon dispersion and possible complete frequency band gaps due to Bragg reflections or/and local resonances, which can be controlled by geometry and material properties. Another approach to modify the phonon dispersion relies on spatial confinement. Here, the dynamic behaviour at reduced characteristic dimensions has been found to be completely different than for bulk materials. I will report on experimental (Brillouin light scattering) and theoretical (finite element method) evidence of both phononic properties (zone folding, band gap and local resonance) and phonon confinement in one-dimensional Si surface PnCs and two-dimensional Si membrane based PnCs. Additionally, I will discuss the influence of the phononic patterning and phonon confinement on thermal properties (Raman thermometry) and potential applications of PnCs in thermoelectric devices.
    [1] N. Gomopoulos, D. Maschke, C. Y. Koh, E. L. Thomas, W. Tremel, H.-J. Butt, and G. Fytas, Nano Lett. 10, 980 (2010).
    [2] B. Graczykowski, S. Mielcarek, A. Trzaskowska, J. Sarkar, P. Hakonen, and B. Mroz, Phys. Rev. B 86, 085426 (2012).
    [3] B. Graczykowski, M. Sledzinska, N. Kehagias, F. Alzina, J. S. Reparaz, C. M. Sotomayor Torres, APL 104, 123108 (2014).
    [4] V. A. Fonoberov and A. A. Balandin, Nano Lett. 5, 1920 (2005).
    [5] J. Cuffe, E. Chvez, A. Shchepetov, P.-O. Chapuis, E. H. El Boudouti, F. Alzina, T. Kehoe, J. Gomis-Bresco, D. Dudek, Y. Pennec, B. Djafari-Rouhani, M. Prunnila, J. Ahopelto, and C. M. Sotomayor Torres, Nano Lett. 12, 3569 (2012).
    [6] A. Alofi and G. P. Srivastava, Phys. Rev. B 87, 115421 (2013).
    [7] B. Graczykowski, J. Gomis-Bresco, F. Alzina, J. S. Reparaz, A Shchepetov, M Prunnila, J Ahopelto, C.M. Sotomayor Torres, New J. Phys. 16, 073024 (2014).
    Chair: Prof. Maciej Krawczyk
  263. /219/
    Date: Wednesday 2014.07.02
    Speaker: Prof. Maciej Kozak
    Title: Time-resolved SAXS studies of human cystatin C - first observation of radiation induced domain swapping
    Authors: Maciej Kozak1, Michał Taube1, Magdalena Murawska1, Aneta Szymanska2, Anders Grubb3
    1Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
    2Department of Medicinal Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
    3Department of Clinical Chemistry, Lund University, Lund, Sweden
    Abstract: Damaging effects of synchrotron radiation were observed for the wide range of biological samples, ranging from protein crystals to biological cells and tissues [1,2]. Most often these damages were manifested as radiolysis of the tested molecules. However, so far were not observed any conformational changes (such as domain swapping) in the protein structures induced by the synchrotron radiation.
    The aim of this study was to observe the early stages of dimerization of human cystatin C (HCC) via the domain swapping mechanism. The time-resolved small angle scattering experiments were performed using synchrotron radiation on P12 BioSAXS beam line with very short acquisition time (50 ms) at PETRA III synchrotron (DESY Hamburg). Solution scattering data were subjected to detailed analysis by using SVD methods and MCR-ALS as well as the shape determination. Besides the monomeric forms of human cystatin C, also fractions of dimers and higher oligomeric forms of HCC formed even after 50-ms exposure were identified. In addition we showed directly for first time that the formation of human cystatin C oligomers and fibryls was directly preceded by the formation of domain swapped dimer.
    [1] Borek, D.; Dauter, Z.; Otwinowski, Z. (2013) J. Synchr. Rad. 20, 37-48.
    [2] Chen, Heyu; He, Xin; Sheng, Caibin; Ma, Yingxin; Nie, Hui; Xia, Weiliang; Ying, Weihai (2011) Int. J. Physiol. Patophysiol. Pharmacol. 3, 243-248.
    Chair: Prof. Michał Banaszak
  264. /218/
    Date: Tuesday 2014.07.01
    Speaker: Prof. Maciej Radosz
    Affiliation: Soft Materials Laboratory, University of Wyoming, U.S.A.
    Title: Multiblock micelle and dendrimer carriers for cancer drugs
    Abstract: Toxic hydrophobic drugs can be delivered to cancer tissue using benign nano-sized carriers made of block copolymers, dendrimers, or dendrimer-in-liposome particles. Polymeric carriers prepared via micellization in non-aqueous near-critical solvents, referred to as Near-Critical Micellization, have been demonstrated to lead to a much higher drug loading, by as much as a factor of three and to inhibit its premature release. This will be illustrated with examples for PEG-b-PLLA-b-PCL nanoparticles loaded with a model cancer drug paclitaxel. Such triblock nanoparticles are found to be not only solvent-free and paclitaxel-rich, which reduces the body exposure to the excipients, but also nearly burst-release-free, which enhances their therapeutic efficacy. Dendrimer-in-liposome carriers, in turn, provide a unique opportunity to address two other, seemingly contradictory drug-delivery requirements, namely a large size and hence good stability while in circulation but small size and hence rapid diffusion while penetrating the tumor tissue.
    Chair: Prof. UAM Michał Banaszak
  265. /217/
    Date: Wednesday 2014.06.18
    Speaker: Dr Artur Barasiński
    Affiliation: Institute of Physics, University of Zielona Góra
    Title: Generation of maximally entangled states in optical supperlattices
    Abstract: We discuss a model with ultra-cold atoms confined in optical superlattices. In particular, we study the ground-state properties of our system. Applying model involving spin-1 bosons trapped in a double-well potential, we quantify the bipartite entanglement between particles. Depending on the external magnetic field and biquadratic interactions different phases of magnetic order are realized and hence, various phases of the system's entanglement. We show that changing the values of the parameters determining superlattices, we can switch the system among various maximally entangled states. What is important, our model seems to be a good candidate for practical realization of the device which can be a switchable tool for generation on demand of such a states.
    [1] A. Barasiński, W. Leoński, T. Sowiński, to appear in JOSA B (2014).
    Chair: Prof. UAM Adam Miranowicz
  266. /216/
    Date: Wednesday 2014.06.11
    Speakers: Prof. Bogusław Mróz and M.Sc. Piotr Graczyk
    Affiliation: Zakład Fizyki Kryształów, WF UAM
    Title: On the strong elasto-magnetic coupling in ferromagnetic thin film sputtered onto ferroelastic substrate
    Abstract: The influence of substrate ferroelastic phase transition on the magnetization of ferromagnetic thin film was investigated. Two different ferroic materials have been used: ferroelastic/ferroelectric Gd2(MoO4)2 and pure ferroelastic LiCsSO4 as a substrates. A nickel and permalloy thin films, with the different thickness from 10 to 100 nm were used.
    Our measurements showed strong magnetization change at Curie point, which reflect the temperature changes of spontaneous deformation of the samples.
    A strain-driven spin reorientation transitions were described theoretically using a magnetic domain theory. It was shown that magnetization reorientations occurs due to magnetoelastic contribution to free energy and thus affect total magnetization value of a sample. Results of our simulations were found to be in good agreement with the experiments.
    The preliminary results of Brillouin scattering on spin waves propagating in our samples will be shown.
    Chair: Prof. UAM Maciej Krawczyk
  267. /215/
    Date: Wednesday 2014.06.11
    Speaker: Dr Mieczysław Torchała
    Affiliation: Biomolecular Modelling Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
    Title: Studying protein-protein binding funnels with SwarmDock Server and RaTrav
    Abstract: Protein-protein interactions drive many of the biological functions of the cell. Any two proteins have the potential to interact; however, whether the interactions are of biological significance is dependent on a number of complicated factors. Thus, modelling the three-dimensional structure of protein-protein complexes is still considered to be a complex endeavour. In addition to correct protein-protein complex 3D structure returned by the algorithm, equally important is dynamics of binding, i.e., how proteins find their binding partners in the multidimensional space of conformational transitions and how their binding partners, upon complex formation, sample binding funnels, i.e. what is the structure of conformational states space and in which manner proteins change their conformations when traversing this network. We recently released two freely available tools: SwarmDock Server (a web service for the flexible modelling of protein-protein complexes) [1] and RaTrav (a tool for calculating mean first-passage times) [2]. In this talk we share our experience related to conformational state network generation, its structure and dynamics. We successfully applied occupancy probabilities to distinguish between false positive and true positive protein-protein binding funnels [3]and mean first-passage times to find the favourable path and limiting transitions in the true positive protein-protein binding funnel [2].
    [1] M. Torchala, I.H. Moal, R.A.G. Chaleil, J. Fernandez-Recio, P.A. Bates, 'SwarmDock: a server for flexible protein-protein docking', Bioinformatics 29, 807-809 (2013).
    [2] M. Torchala, P. Chelminiak, M. Kurzynski, P.A. Bates, 'RaTrav: a tool for calculating mean first-passage times on biochemical networks', BMC Syst. Biol. 7, 130 (2013).
    [3] M. Torchala, I.H. Moal, R.A.G. Chaleil, R. Agius, P.A. Bates, 'A Markov-chain model description of binding funnels to enhance the ranking of docked solutions', Proteins: Structure, Function, and Bioinformatics 81, 2143-2149 (2013).
    Chair: dr Przemysław Chełminiak
  268. /214/
    Date: Tuesday 2014.06.10
    Speaker: M.Sc. Mikołaj Lasota
    Affiliation: Faculty of Physics, Astronomy and Applied Informatics, Nicolaus Copernicus University, Toruń
    Title: Elementary linear optics quantum repeater links with realistic single photon sources
    Abstract: I study operation of realistic elementary quantum repeater links constructed using multiple single photon sources, quantum memories, linear optics, and heralding detectors. Two schemes are considered. The first one is the well established one-photon scheme which produces a photon in a delocalized superposition state between two quantum repeater nodes, each of them fed with one single photon at the input. The second one is a linear optics analog of the robust scheme based on interfering two Stokes photons emitted by atomic ensembles, which does not require phase stability between the repeater nodes. Imperfect photon sources are assumed, generating outputs with both vacuum and multiphoton contributions. I find conditions for the source photon statistics that guarantee generation of entanglement in the relevant qubit subspaces and compare it with classicality criteria. I also quantify the amount of entanglement that can be produced with imperfect single photon sources, optimized over setup parameters, using as a measure entanglement of formation. Finally, I discuss verification of the generated entanglement by testing Bell's inequalities.
    Chair: Prof. UAM Adam Miranowicz
  269. /213/
    Date: Monday 2013.06.09
    Speaker: Prof. Keith E. Gubbins
    Affiliation: Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, U.S.A.
    Title: Wetting at the Nano-Scale
    Abstract: At the macro-scale the extent to which a liquid wets a solid substrate is usually described in terms of the contact angle, θc, and the surface tensions involved. Depending on the liquid and substrate, the system is described as amphiphilic ('wetting', θc < 90o) or amphiphobic ('non-wetting', θc > 90o). Such a description has a number of limitations; in particular, it breaks down for sufficiently small nano-scale systems, and is limited to describing liquid, as opposed to gaseous or solid, adsorbed films. At a more fundamental level, wetting is determined by the competition between the adsorbate-substrate intermolecular forces and the adsorbate-adsorbate forces. Through a corresponding states analysis of the statistical mechanical description of such wetting systems it is possible to define a microscopic wetting parameter, aw, that is a measure of wetting that applies at all scales and for any kind of adsorbed film (gas, liquid or solid) [1,2].
    We illustrate the usefulness of this wetting parameter by considering the properties of a nano-phase confined within a porous material. In this case the dimensionless pore width, pore shape and wetting characteristics of the confined phase are of particular importance. Examples drawn from both experiment and molecular simulation studies will be presented for phase separations, selective adsorption in the case of mixtures, and pressure enhancement, with emphasis on simple pore geometries. These examples illustrate the central role played by wetting, and also the breakdown of some concepts and macroscopic laws, such as Gibbs' surface thermodynamics for nano-phases confined within small pores.
    [1] R. Radhakrishnan, K.E. Gubbins and M. Śliwińska-Bartkowiak, "Global Phase Diagrams for Freezing in Porous Media", Journal of Chemical Physics, 116, 1147-1155 (2002).
    [2] Keith E. Gubbins, Yun Long and Małgorzata Śliwińska-Bartkowiak, "Thermodynamics of Confined Nano-Phases", Journal of Chemical Thermodynamics, 74, 169-183 (2014).
    Chair: Prof. Małgorzata Śliwińska-Bartkowiak
  270. /212/
    Date: Wednesday 2014.06.4
    Speaker: Dr Mirosław Łabuz
    Affiliation: Department of Theoretical Physics, Faculty of Mathematics and Natural Sciences, University of Rzeszów, Pigonia 1, 35-310 Rzeszów
    Title: String hypothesis for short Heisenberg magnets
    Abstract: It is well known, that exact Bethe Ansatz solutions for the Heisenberg eigenproblem of a linear magnetic chain base upon the hypothesis of strings. This hypothesis is presumed to work in the thermodynamic limit N→∞, but it works pretty well also in the finite case. I present some details of analysis performed for short magnetic chains. In particular, I exploit Galois symmetry associated with the secular eigenproblem in determining rigged string configurations.
    Chair: Prof. UAM Adam Miranowicz
  271. /211/
    Date: Thursday 2014.05.29
    Speaker: B.Sc. Justyna Łodyga
    Affiliation: Zakład Elektroniki Kwantowej, WF UAM
    Title: Simple single-shot protocol for encoding and decoding an unknown qubit state into various topological codes
    Abstract: I present a general scheme for encoding and decoding an unknown qubit state into various topological codes for quantum error correction. I illustrate this method by means of Kitaev planar code, where qubits are arranged in a two-dimensional array on a surface of nontrivial topology. I also show that in the noisy scenario (when state preparation and measurements are faulty) an analytical bound for the fidelity of a quantum communication can be easily provided following the scheme and is of order of noise acting on a single physical qubit, in a large code size limit.
    Chair: Prof. UAM Adam Miranowicz
  272. /210/
    Date: Wednesday 2014.05.28
    Speaker: B.Sc. Justyna Łodyga
    Affiliation: Zakład Elektroniki Kwantowej, WF UAM
    Title: Introduction to quantum error correction codes
    Abstract: Protecting quantum information from errors due to decoherence and other quantum noise is crucial for fault-tolerant quantum computation. In order to do quantum information processing reliably in the presence of noise, the theory of error-correcting codes has been developed. These codes work by encoding quantum states in a special way that make them resilient against the effects of noise, and then decoding when it is wished to recover the original state. I start my presentation with comprehensive introduction to quantum error correction theory. Then, I carry on with short description of topological quantum error-correcting codes, an important class of quantum codes.
    Chair: Prof. UAM Adam Miranowicz
  273. /209/
    Date: Thursday 2014.05.22
    Speaker: Dr Andrii Chumak
    Affiliation: Fachbereich Physik and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
    Title: Magnons as an alternative to a charge current
    Abstract: With conventional CMOS technology data is carried by flows of electrons that generate heat which is responsible for the device's power consumption. An alternative to this principle is the employment of other particles or quasi-particles as information carriers which are subject to dissipation to a lesser degree than electrons. I will show that eigen excitations of magnetic media - magnons can be used for this role.
    In my talk, after an introduction on spin waves and their quanta magnons, I will concentrate on the artificial magnetic materials with periodically-modulated magnetic properties - magnonic crystals. Several different designs of macro- and micro-scaled magnonic crystals will be discussed [1-3]. In the second part of the talk, the magnon-based data processing elements will be shown: time reverser of microwave pulses [4] and magnon transistor. These proof of concept devices are made out of an insulator in order to exclude any motion of free electrons and are based on magnonic crystals. The time reverser is based on a dynamic magnonic crystal: a crystal with properties that can be varied using external controls on a very fast time scale. We have shown that a wave packet, while being reflected by the dynamic crystal, reverses its time profile [4]. The magnon transistor is the device operational principle of which is based on the control of magnons by magnons. It was realized through an enhancement of nonlinear magnon interactions in a magnonic crystal. We have shown that the transistor allows for the design of all-magnon logic gates as well as for enhancement of magnonic signals. The final part of the talk will be devoted to the miniaturization issues of the insulator-based magnonics. Very recently we have studied spin-wave excitation and propagation in an insulator yttrium-iron-garnet spin-wave waveguide of micrometer sizes [5]. These results represent a valid step towards the nano-scaled particle-less technology in which information is carried and processed by magnons rather than by electrons.
    [1] A.V. Chumak, et al., Phys. Rev. Lett. 108, 257207 (2012).
    [2] A.V. Chumak, et al., Appl. Phys. Lett. 95, 262508 (2009).
    [3] B. Obry, et al., Appl. Phys. Lett. 102, 202403 (2013).
    [4] A.V. Chumak, et al., Nat. Commun. 1:141 doi: 10.1038/ncomms1142 (2010).
    [5] P. Pirro, et al., Appl. Phys. Lett. 104, 012402 (2014).
    Chair: Prof. UAM Maciej Krawczyk
  274. /208/
    Date: Tuesday 2014.05.20
    Speaker: Prof. Nobuyuki Imoto
    Affiliation: Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Osaka, Japan
    Title: Two-state formalism
    Abstract: A procedure to obtain the expectation value of an arbitrary observable is referred to as "state." Usually, such "state" has one-to-one correspondence to the quantum state of the physical system. In some cases, however, we know not only the prepared quantum state but also the post-selected state, which we actually see. If we estimate the measurement result performed by the third party intermediately, such mathematical "state" contains two physical states: initial and final states. Sometimes, we can precisely estimate the value of the conjugate observables regardless with his/her choice [1]. The "state" of course depends on the measurement, but the expression becomes simple for the weak measurement and strong measurement. For the weak measurement, it becomes the weak value [2], which exhibits interesting properties in paradoxical situations [3,4].
    [1] K. Shimizu, et. al.: Phys. Rev. A 84, 022308 (2011).
    [2] Y. Aharonov, et. al.: Phys. Rev. Lett. 60, 1351 (1988).
    [3] Y. Aharonov, et. al.: Phys. Lett. A 301, 130 (2002).
    [4] J. S. Lundeen and A. M. Steinberg, Phys. Rev. Lett. 102, 020404 (2009);
        K. Yokota et. al., New J. Phys. 11, 033011 (2009).
    Chair: Prof. UAM Adam Miranowicz
  275. /207/
    Date: Thursday 2014.05.15
    Speaker: Dr Karol Załęski
    Affiliation: Centrum NanoBioMedyczne UAM
    Title: Properties of magnetic Heusler alloys - experimental and theoretical approach (part II)
    Abstract: Heusler alloys are a class of materials with diverse physical properties and many potential applications. Depending on their specific composition they can exhibit half-metallic ferromagnetism (full spin polarization at the Fermi level), magnetic shape memory (martensitic transformation in a ferromagnetic state), among others. The Heusler alloys Ni-Mn-Sn belong to a family of magnetic shape memory alloys. This magnetostructural transformation leads to magnetocaloric effect, modification of exchange coupling, large magnetoresistance, etc. The comprehensive experimental investigation of magnetic, transport and structural properties of Ni-Mn-Sn thin films was undertaken as well as ab initio calculations. It was shown that the local atomic configuration affects on magnetic properties. The estimated values of the martensitic transformation temperature and Curie (Néel) temperature were collected in the form of phase diagram.
    Chair: Prof. UAM Maciej Krawczyk
  276. /206/
    Date: Wednesday 2014.05.14, 12:00
    Speaker: Dr hab. Genowefa Ślósarek
    Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM
    Title: Denaturacja i agregacja białek (Denaturation and aggregation of proteins)
    Abstract: Z chwilą, gdy rozwinęły się badania nad przyczyną chorób wywołanych przez amyloidy, rozbudowane zostały również badania podstawowe dotyczące procesu agregacji białek. Wykazano szybko, że proces agregacji występuje stosunkowo często i generalnie może to być proces odwracalny (w niektórych przypadkach in vivo) lub nieodwracalny (także w szczególnych przypadkach zmian fizjologicznych). Powstające agregaty mają często formę uporządkowanych, regularnych struktur. Wykazano także, że proces agregacji ściśle wiąże się z denaturacją cząsteczek białkowych.
    Chair: Prof. UAM Michał Banaszak
  277. /205/
    Date: Thursday 2014.05.8
    Speaker: Dr Karol Załęski
    Affiliation: Centrum NanoBioMedyczne UAM
    Title: Properties of magnetic Heusler alloys - experimental and theoretical approach (part I)
    Abstract: Heusler alloys are a class of materials with diverse physical properties and many potential applications. Depending on their specific composition they can exhibit half-metallic ferromagnetism (full spin polarization at the Fermi level), magnetic shape memory (martensitic transformation in a ferromagnetic state), among others. The Heusler alloys Ni-Mn-Sn belong to a family of magnetic shape memory alloys. This magnetostructural transformation leads to magnetocaloric effect, modification of exchange coupling, large magnetoresistance, etc. The comprehensive experimental investigation of magnetic, transport and structural properties of Ni-Mn-Sn thin films was undertaken as well as ab initio calculations. It was shown that the local atomic configuration affects on magnetic properties. The estimated values of the martensitic transformation temperature and Curie (Néel) temperature were collected in the form of phase diagram.
    Chair: Prof. UAM Maciej Krawczyk
  278. /204/
    Date: Tuesday 2014.04.29, 12:00
    Speaker: Prof. Robert Hołyst
    Affiliation: Dyrektor Instytutu Chemii Fizycznej PAN w Warszawie
    Title: Artificial and biological engines
    Abstract: I will discuss two issues related to the performance of artificial and biological engines. Three cases will be presented: ferroelectric liquid crystal monolayer performing continuous rotation in a monolayer of 3nm size powered by the flux of water; ATP as a biological pump powered by the flux of protons and finally kinesin motion along microtubules. In these three cases we will discuss the power of such engines and their resistance to thermal noise and local energy barriers induced by crowding by linear polymers.
    Chair: Prof. UAM Michał Banaszak
  279. /203/
    Date: Wednesday 2014.04.23, 12:00
    Speaker: Dr hab. Jarosław S. Kłos
    Affiliation: Zakład Fizyki Komputerowej, Wydział Fizyki UAM
    Title: Simulations of neutral and charged dendrimers
    Abstract: We study the properties of neutral and charged dendrimers with flexible spacer-chains of various lengths and explicit counterions using Monte Carlo simulations based on the bond fluctuation model. For neutral dendrimers with the excluded volume interactions our simulations confirm the theoretical prediction for the scaling behavior of the dendrimer size. For charged dendrimers the full Coulomb potential is taken into account with the reduced temperature τ as the main control parameter. Our simulations show an interplay of counterion condensation, trapping of counterions inside the dendrimer's volume and counterion evaporation into the solution which give rise to a non-monotonous electrostatic swelling of the molecule with τ. To explain the swelling effect we apply a Flory-type argument where both trapped but non-condensed counterions and uncompensated charges due to counterion evaporation are included. This model properly reflects the swelling behavior with respect to temperature, pH and spacer-length variation, though quantitatively underestimates it.
    Chair: Prof. UAM Adam Miranowicz
  280. /202/
    Date: Wednesday 2014.04.16
    Speaker: Dr Maciej Misiorny
    Affiliations: (1) Forschungszentrum Jülich, Peter Grünberg Institut, Theoretical Nanoelectronics Division (PGI-2), 52425 Jülich, Germany and (2) Mesoscopic Physics Division, Physics Faculty, AMU.
    Title: Spintronic magnetic anisotropy
    Abstract: Experimental techniques nowadays allow for detailed transport measurements of individual atoms [1] or molecules [2,3] that exhibit magnetic anisotropy. The superparamagnetism of these systems, i.e. the preferential alignment of their spins along an easy axis, is a useful effect for nanoscale applications as it prevents undesired spin reversal. It has been suggested [4], and also experimentally proven for magnetic atoms [5], that spin-polarized currents can be employed to control the magnetic state of such systems assuming a given, intrinsic anisotropy. Furthermore, it has been also demonstrated that magnetic anisotropy can play a major role in formation of the Kondo effect in nanoscopic systems [1,3]. However, the spintronic transport also changes the magnetic anisotropy that it tries to probe and therefore these two cannot be treated separately. In fact, we have recently shown that any spin-isotropic high-spin quantum dot coupled to ferromagnets can acquire superparamagnetic properties in a spintronic way, i.e. from the outside via an effective quadrupolar exchange field [6]. The talk will review various theoretical aspects of transport through nanoscopic systems displaying magnetic anisotropy, with the main emphasis on how the flow of spin-polarized current through such a molecule/adatom can induce the magnetic anisotropy.
    [1] A.F. Otte et al., Nature Phys. 4, 847 (2008).
    [2] H.B. Heersche et al., Phys. Rev. Lett. 96, 206801 (2006); A. Zyazin et al., Nano Lett. 10, 3307 (2010); E. Burzuri et al., Phys. Rev. Lett. 109, 147203 (2012).
    [3] J.J. Parks et al., Science 328, 1370 (2010).
    [4] M. Misiorny and J. Barnaś, Phys. Rev. B 75, 134425 (2007); Phys. Rev. Lett. 111, 046603 (2013).
    [5] S. Loth et al., Nature Phys. 6, 340 (2010).
    [6] M. Misiorny, M. Hell and M. Wegewijs, Nature Phys. 9, 801 (2013).
    Chair: Prof. Adam Miranowicz
  281. /201/
    Date: Thursday 2014.04.10
    Speaker: Prof. Jean-Claude S. Levy
    Affiliation: Matériaux et Phénome`nes Quantiques, Université Paris, France
    Title: Magnetic structures of 2D/3D nanoparticles
    Abstract: Magnetic nanoparticles have many applications, from printing to medical treatments, electronic memories and radio frequency devices, but their magnetic structure is still not well known. After a short review of one century of observations of magnetic domains in magnetic particles and magnetic nanoparticles especially on 2D particles, comments will be given on last twenty years of numerical simulations. A short review of the magnetic dynamics of such particles and nanoparticles will also be given. Then analytic considerations on magnetic structures of 2D and 3D nanoparticles will be reported as well as basic models for the magnetic structure of small enough nanoparticles. Finally recent numerical results on the magnetic structure of 2D and 3D nanoparticles and their dynamics will be given.
    Chair: Prof. UAM Maciej Krawczyk
  282. /200/
    Date: Tuesday 2014.04.8
    Speaker: Prof. Yuri Gorobets
    Affiliation: Institute of Magnetism, National Academy of Sciences of Ukraine, Kiev, Ukraine
    Title: Biogenic nanomagnetism
    Abstract: The lecture contains the review of the experimental data about the biogenic magnetic nanoparticles (BMNs) in different organisms. The BMNs became the object of intensive research since 1975 when the BMNs were detected in magnetotactic bacteria (MTB) for the first time. The literature data about the proteins of the so-called magnetosome island of MTB will be represented concerning the process of biomineralization of BMNs. The physiological origin of BMNs, their possible functions in multi-cellular organisms and interrelation with the number of human diseases will be considered on the basis of the bioinformatics methods and magnetochemical effects.
    Chair: Prof. UAM Maciej Krawczyk
  283. /199/
    Date: Wednesday 2014.04.2
    Speaker: Dr Karol Bartkiewicz
    Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
    Title: Efficient Amplification of Photonic Qubits by Optimal Quantum Cloning
    Abstract: We demonstrate a phase-independent quantum amplifier of a polarization qubit which can outperform the heralded qubit amplifier [S. Kocsis et al., Nature Physics 9, 23 (2013)]. It employs the multi-functional cloner in 1 to 2 copying regime, capable of providing approximate copies of qubits given by various probability distributions, and is optimized for distributions with axial symmetry. The direct application of the proposed solution is possible in quantum technologies, doubling the range where quantum information is coherently broadcast. It also outperforms natural nonlinear amplifiers that use stimulated emission in bulk nonlinear materials. We consider the amplifier to be an important tool for amplifying quantum information sent via quantum channels with phase-independent damping.
    Chair: Prof. UAM Adam Miranowicz
  284. /198/
    Date: Wednesday 2014.03.26
    Speaker: Dr Krzysztof Dobek
    Affiliation: Quantum Electronics Division, Faculty of Physics, AMU
    Title: New approaches in tunable optics
    Abstract: During the talk I will present modern techniques that allow to actively controlling the optical properties of a single optical element e.g. the lens focal length. First I will show widely used macroscopic devices, used for instance in astronomy, then emerging microscopic devices developed recently. Finally, I will present our efforts in the development of a flexible focal length device, whose operation is based on a new thermo-optical technique.
    Chair: Prof. UAM Adam Miranowicz
  285. /197/
    Date: Wednesday 2013.03.19
    Speaker: Prof. Mirosław Dudek
    Affiliation: Institute of Physics, University of Zielona Góra
    Title: Mean field method with space dependent order parameter
    Abstract: A new and efficient algorithm for the mean-field approximation is presented, in which we do not need to solve explicitly the self-consistent condition. This algorithm is a modification of the Metropolis algorithm which is often used in Monte Carlo simulations.
    Chair: Prof. UAM Michał Banaszak
  286. /196/
    Date: Wednesday 2014.03.12
    Speaker: Prof. Michał Banaszak
    Affiliation: Quantum Physics Division, Physics Faculty, AMU
    Title: From Fractal Chaos to Regular Patterns and Vice Versa. Self-Organisation in Spatial Systems
    Abstract: This study offers a new perspective on the spatial impacts generated by cities or urban agglomerations. These impacts can range from chaotic to fully ordered. We demonstrate that cities produce a wealth of gravitational attractors whose size and shape depend on the resistance of space emerging inter alia from transport friction costs. This finding offers original insights into the complex evolution of spatial systems and appears to be consistent with the principles of central place theory known from spatial sciences and geography. Our approach is dynamic in nature and forms a generalization of hierarchical principles in geographic space.
    Chair: Prof. UAM Maciej Krawczyk
  287. /195/
    Date: Wednesday 2014.03.5
    Speaker: Prof. Grzegorz Pawłowski
    Affiliation: Zakład Stanów Elektronowych Ciała Stałego, WF UAM
    Title: Zastosowanie środowiska ALPS (2.1) do obliczeń w układach silnie skorelowanych
    Abstract: W ramach wykładu zaprezentowana zostanie najnowsza wersja 2.1.1 środowiska Algorithms and Libraries for Physics Simulations (ALPS) [1] wraz z jego zastosowaniami. ALPS jest projektem typu open source rozwijanym od roku 2004 przez międzynarodową grupę fizyków teoretyków specjalizujących się w badaniu układów silnie skorelowanych [2].
    Wszystkie elementy pakietu wykorzystują wspólny format danych zapisanych w języku XML. Na tym poziomie przeprowadzenie symulacji nie wymaga znajomości programowania w języku C++, w jakim zostały napisane biblioteki obliczeniowe i główne aplikacje.
    Gotowe programy obejmują implementacje najważniejszych algorytmów dla modeli kwantowych na sieci, jak np.: klasyczne i kwantowe Monte Carlo (spinMC, QMC) w wersji lokalnej i klasterowej, kwantowe symulacje typu Wanga-Landaua (QWL), dokładna i pełne diagonalizacja (ED), macierz gęstości grupy renormalizacji (DMRG) czy dynamiczne pole średnie (DMFT).
    Zawarte w projekcie biblioteki stanowią ramy do rozwoju własnego oprogramowania z wykorzystaniem obliczeń równoległych typu openMPI na różnych platformach sprzętowych i systemowych.
    W nowej wersji 2 oprogramowania ALPS uwzględniono wykorzystanie standardu HDF5 do zapisu i zarządzania danymi, użycie specjalistycznych narządzi do analizy wyników napisanych w języku Python oraz integrację pracy całego systemu w środowisku do wizualizacji procesów obliczeniowych VisTrails.
    Wykład uzupełniony będzie o liczne przykładowe obliczenia.
    [2] B.Bauer et al. (ALPS collaboration), "The ALPS project release 2.0: open source software for strongly correlated systems", J.Stat.Mech. P05001 (2011).
    Chair: Prof. UAM Michał Banaszak
  288. /194/
    Date: Thursday 2014.02.27
    Speaker: Dr Ryszard Gieniusz
    Affiliation: Uniwersytet w Białymstoku
    Title: Fale spinowe w strukturyzowanych warstwach granatów
    Abstract: Przedstawione zostaną wybrane efekty zachowania się fal spinowych w strukturyzowanych warstwach granatu itrowo-żelazowego. Omówione będzie oddziaływania fal spinowych z: (i) pojedynczym otworem - zjawisko dyfrakcji fal spinowych; (ii) linią otworów - efekt całkowitego wewnętrznego odbicia tych fal; (iii) dwuwymiarową sieci otworów. Badania wykonano z wykorzystaniem: (i) klasycznego spektrometru nieelastycznego rozpraszania światła Brillouina (BLS) z rozdzielczością czasową i przestrzenną w konfiguracji odbiciowej i transmisyjnej, (ii) mikroskopu BLS pracującego w konfiguracji odbiciowej z rozdzielczością przestrzenną do ok. 300 nm; (iii) spektrometru FMR. Wyniki eksperymentalne interpretowano korzystając między innymi z modelowania mikromagnetycznego. Dodatkowo przedstawione będą, planowane do dalszych badań, nowe struktury magnoniczne w oparciu o naświetlane jonami magnetyczne nanostruktury.
    Chair: Prof. UAM Maciej Krawczyk
  289. /193/
    Date: Wednesday 2014.02.26 at 13:00
    Speaker: Prof. Dagomir Kaszlikowski
    Affiliation: Centre for Quantum Technologies, National University of Singapore
    Title: The triangle principle: new approach to non-classical correlations
    Abstract: We study an application of an information-theoretic distance between two measurements to investigate non-classical correlations. We postulate the triangle principle, which states that any information-theoretic distance is well defined on any pair of measurements, even if these measurements cannot be jointly performed. As a consequence, the triangle inequality for this distance is obeyed for any three measurements. This simple principle is valid in any classical realistic theory, however it may not hold in quantum theory. It leads to derivation of certain inequalities whose violations are indicators of non-classicality. Some of these inequalities formally look the same as those found in the literature on local realism and non-contextuality but we also derive completely new inequalities. We also show that our geometrical approach naturally implies monogamy of non-classical correlations.
    Chair: Prof. UAM Maciej Krawczyk
  290. /192/
    Date: Monday 2014.02.24
    Speaker: Prof. Peter Nijkamp
    Affiliation: Professor of Regional Economics and Economic Geography at the Vrije Universiteit, Amsterdam, the Netherlands, a fellow of the Tinbergen Institute and President of the Governing Board of the Netherlands Research Council (NWO).
    Title: Virtual reality: The death of distance revisited.
    Chair: Prof. UAM Michał Banaszak
  291. /191/
    Date: Wednesday 2014.02.19
    Speaker: Dr Paweł Kurzyński
    Affiliation: Centre for Quantum Technologies, National University of Singapore and Faculty of Physics, Adam Mickiewicz University
    Title: How to test indistinguishability of particles
    Abstract: My talk will consist of two parts. First, we propose a test to measure the bosonic and fermionic quality of particles with respect to physical operations of single-particle addition and subtraction. We apply our test to investigate bosonic properties of composite particles made of an even number of fermions and suggest its experimental implementation. Next, we show that under certain assumptions one can derive a variant of Specker's non-contextual inequality for a system of three indistinguishable bosonic particles. The inequality states that the sum of probabilities of three pairwise exclusive events is bounded by one. This inequality cannot be violated using standard quantum mechanical projectors and cannot be violated by independent distinguishable particles. On the other hand, due to bosonic properties this bound is violated up to 3/2. We also argue that the violation of this inequality can be considered as a test of bosonic nature.
  292. /190/
    Date: Wednesday 2014.02.12
    Speaker: Prof. Jacek Gapiński
    Coauthors: Prof. Adam Patkowski and Prof. Gerhard Naegele
    Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM
    Title: Struktura, dynamika i krystalizacja układów koloidalnych typu Yukawy. Część II.
    (Structure, dynamics and crystallization of Yukawa type colloidal systems. Part II.)
    Abstract: In the preceding talk, prof. Adam Patkowski explained the methods and tools which have been used to calculate the pair correlation function g(r) and the structure factor S(q) of colloidal systems with Yukawa-type interactions. Using these tools we managed to calculate the freezing lines of such systems both using experimentally measurable parameters and generalized parameters. In the latter case a master curve was obtained. In this part I am going to discuss the information accessible from the pair correlation function g(r) which describes the local structure of colloidal systems. In particular, I will show such parameters as the number of nearest neighbors, mean nearest neighbor distance, position of the maximum of g(r), and peak position of S(q). Conclusions drawn from the values obtained at freezing lines will be extended to colloidal systems in fluid state, leading to surprising results concerning the local structure of strongly interacting colloids.
  293. /189/
    Date: Wednesday 2014.02.5
    Speaker: Prof. Adam Patkowski
    Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM oraz Centrum NanoBioMedyczne UAM
    Title: Struktura, dynamika i krystalizacja układów koloidalnych typu Yukawy. Część I.
    (Structure, dynamics and crystallization of Yukawa type colloidal systems. Part I.)
    Abstract: Oddziaływania w zawiesinach naładowanych koloidów opisane są przez efektywną energię oddziaływań dwójkowych typu Yukawy: u(r)/kBT ∼ AZ2exp(−κr)/r, gdzie A jest stałą układu, κ−1 - długością ekranowania Debye'a, Z - efektywnym ładunkiem cząstki. Uporządkowanie bliskiego zasięgu w układach koloidalnych może być mierzone przy pomocy: dwójkowej funkcji rozkładu radialnego g(r), średniej odległości najbliższych sąsiadów rn i ich liczby Nn. Ostatnie dwie wielkości mogą być obliczone z funkcji g(r). Uporządkowanie dalekiego zasięgu w układach koloidalnych mierzone jest przez zależny od wektora rozpraszania q statyczny czynnik struktury S(q), który może być zmierzony w eksperymencie rozpraszania światła lub nisko-kątowego rozpraszania promieni rentgena (SAXS). Punkt krystalizacji układu koloidalnego dany jest przez kryterium Hansena-Verleta (HV): S(qm)=3. Dynamika układu koloidalnego charakteryzowana jest przez krótko-czasowy współczynnik dyfuzji kolektywnej DC(q), określony jako: DC(q)=D0H(q)/S(q), gdzie D0 jest wartością dla nieskończonego rozcieńczenia układu, a H(q) jest zależną od q funkcją hydrodynamiczną. Wykazaliśmy, przy pomocy statycznego (SAXS) i dynamicznego (XPCS) rozpraszania rentgenowskiego promieniowania synchrotronowego, że modele teoretyczne dla S(q) - równanie całkowe Rogersa-Younga (RY), oraz dla DC(q)-model δγ, dobrze opisują dane doświadczalne uzyskane dla naładowanych koloidów w całym zakresie ciekłym [1]. Stosując model δγ przeanalizowaliśmy zachowanie funkcji hydrodynamicznej H(q) [2], a przy pomocy równania całkowego RY oraz kryterium HV uzyskaliśmy również krzywą krystalizacji [3] dla naładowanych koloidów typu Yukawy w szerokim zakresie ładunku, rozmiarów i stężenia koloidów i stężenia dodanej soli. Ostatnio badaliśmy także punktu krystalizacji.
    [1] J. Gapinski, A. Patkowski, A. J. Banchio, J. Buitenhuis, P. Holmquist, M. P. Lettinga, G. Meier and G. Nägele, J. Chem. Phys. 130 (2009) 084503.
    [2] J. Gapinski, A. Patkowski and G. Nägele, J. Chem. Phys. 132 (2010) 054510.
    [3] J. Gapinski, G. Nägele, and A. Patkowski, J. Chem. Phys. 136 (2012) 024507.
  294. /188/
    Date: Wednesday 2014.01.29
    Speaker: Dr Sławomir Mamica
    Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
    Title: Spin-wave spectra of two-dimensional circularly magnetized nanodots and nanorings
    Abstract: The properties of small magnetic dots are the object of increased interest because of their rich physics and potential applications in a variety of fields, such as data storage and information processing, single magnetic nanoparticle sensing and trapping, microwave-frequency oscillators, or frequency multiplication. The physical phenomena observed in small magnetic dots are related to their minute dimensions, ranging from tens of nanometers to a few micrometers, and the competition between the long-range dipolar interaction and the short-range exchange interaction. In small magnetic dots their concurrence leads, among other effects, to a rich spectrum of stable and metastable magnetic configurations, including vortex states. The chirality and polarity of the vortex are potential information carriers and can be switched with external magnetic field, electric current, or microwave radiation. An important role in magnetization switching, as well as in the stability of magnetic configurations, is played by spin-wave excitations. Moreover, the role of thermally excited spin waves in magnetization switching proves very important even in particles smaller than the exchange length.
    In this work we use a microscopic theory taking into account the dipolar and nearest-neighbour exchange interactions for exploring spin-wave excitations in two-dimensional magnetic dots in the vortex state. Normal modes of different profiles are observed: azimuthal and radial modes, as well as fundamental (quasiuniform) and highly localized modes. We examine the dependence of the frequencies and profiles of these modes on the dipolar-to-exchange interaction ratio and the size of the dot. Special attention is paid to some particular modes, including the lowest mode in the spectrum and the evolution of its profile, and the fundamental mode, the frequency of which proves almost independent of the dipolar-to-exchange interaction ratio. Finally, we study the hybridization of the modes, show the multi-mode hybridization and explain the selection rules.
    [1] S. Mamica et al., J. Phys. D, accepted (2013).
    [2] S. Mamica, J. Appl. Phys., accepted (2014).
  295. /187/
    Date: Tuesday 2014.01.21
    Speaker: Prof. Andrzej Sikorski
    Affiliation: Zakład Teorii Biopolimerów, Wydział Chemii Uniwersytetu Warszawskiego
    Title: The properties of adsorbed polymers
    Abstract: The properties of polymer films formed by adsorbed or tethered chains are important for practical reasons (lubrication, colloidal stabilization, chromatography etc.) and interesting from the theoretical point of view. The adsorption of homo- and copolymers on homogenous and patterned surfaces was a subject of our studies. We employed computer simulations of idealized models as a main tool. The coarse-grained models of macromolecules were designed for this purpose. The properties of the system studied were determined using some versions of the Monte Carlo method. The influence of the temperature, the strength of the adsorption, the sequence of mers, patterns on the surface and the macromolecular architecture on the properties of chains were studied. The results were discussed and compared to other simulations results, theoretical predictions and real experiments.
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    Date: Wednesday 2014.01.15
    Speaker: Dr Sławomir Mamica
    Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
    Title: Stability of the in-plane vortex state in two-dimensional magnetic nanodots and nanorings
    Abstract: A major scientific interest of magnetic nanodots and nanorings lies in the concurrence of the exchange and dipolar interactions. In a variety of systems, long-range interactions have led to a number of interesting findings. However, the concurrence of short-range and long-range interactions proves particularly interesting. Also the magnetic vortex state stems from the competition between the long-range dipolar interaction and the short-range exchange interaction. On the other hand, studies of the possible stable and metastable magnetic configurations in magnetic nanorings are of major importance regarding to the potential applications which extend from data processing and high-density magnetic random access memory (MRAM) elements to microwave frequency oscillators and single magnetic nanoparticle sensors.
    In this work we study two-dimensional nanodots and nanorings composed of elementary magnetic moments arranged in sites of a square lattice. Using a microscopic approach that takes into account the dipolar and nearest-neighbour exchange interactions, we calculate the spin-wave frequencies and profiles to draw conclusions regarding the stability of the assumed magnetic configuration. We show that, in contrast to square rings, in circular rings the exchange-driven reorientation is sensitive to both the external and internal sizes of the ring. We associate this behaviour with the delocalized character of the lowest spin-wave excitation,