Data: 17.10.2019
Miejsce: Sala 422 14:15
Temat: Transport parameters of the quark-gluon plasma: flavour dependence in the quasiparticle model
Osoba: Valeriya Mykhaylova
Opis: It is known that the quark-gluon plasma (QGP) is well described in terms of the relativistic hydrodynamics. Therefore, along with its equation of state and phase diagram, we are also interested in the transport properties of the QGP as a fluid. During the talk, I will present recent results for the shear and bulk viscosities, as well as electrical conductivity, obtained from the relaxation time approximation to Boltzmann equation. The calculations are performed within the quasiparticle model, where dynamical quark and gluon masses depend on the running coupling, extracted from the lattice QCD data.

Data: 10.01.2019
Miejsce: Sala 422 14:15
Temat: Effects of magnetic fields and slow rotation in white dwarfs
Osoba: Diana Alvear Terrero
Opis: We use Hartle’s formalism to study the effects of rotation in the structure of magnetised white dwarfs within the framework of general relativity. We describe the inner matter by means of an equation of state for electrons under the action of a constant magnetic field, which introduces an anisotropy in the pressures. Solutions correspond to typical densities of white dwarfs and values of magnetic field below 10^13G considering perpendicular and parallel pressures independently, as if associated to two different equations of state.

Data: 20.12.2018
Miejsce: Sala 422 14:15
Temat: kappa-deformed BMS symmetry
Osoba: Josua Unger
Opis: In this talk I will give an overview about the use of Hopf algebras in fundamental physics. I will present and discuss the BMS algebra. Furthermore this BMS algebra will be deformed to a Hopf algebra that contains the kappa Poincare algebra.

Data: 13.12.2018
Miejsce: Sala 422 14:15 
Temat: Shear viscosity of the QGP from the relaxation time approximation within the quasiparticle model
Osoba: Valeriya Mykhaylova
Opis: There are experimental evidences that the quark-gluon plasma (QGP) produced in the heavy-ion collisions, is well described in terms of ideal hydrodynamics [1]. However, for more realistic interpretation, the dissipative viscous processes should be taken into account. One of the parameters describing the dissipation of the energy is a shear viscosity, which I have obtained using the relaxation time approximation to the Boltzmann equation. The calculations are performed within the quasiparticle model, in which quarks and gluons have changing (dynamical) masses obtained from the lattice QCD data [2]. [1] E. Shuryak, Prog. Part. Nucl. Phys. 53 (2004) [2] S. Borsanyi et al., Phys. Lett. B 370 (2014) 99-104

Data: 29.11.2018
Miejsce: Sala 422 14:15
Temat: Neutrino energy reconstruction in accelerator-based neutrino-nucleus scattering experiments
Osoba: Alexis Nikolakopoulos
Opis: No abstract provided

Data: 22.11.2018
Miejsce: Sala 422 14:15
Temat: Palatini frames in scalar-tensor theories
Osoba: Aleksander Kozak
Opis: Conformal transformations play an important role in the scalar-tensor theories of gravity, as they allow one to carry out calculations in a more convenient frame, simplifying the field equations. In the Palatini approach, however, the metric structure of space-time is decoupled from its affine structure, so that a transformation of the metric tensor does not entail a corresponding change in the linear connection. One needs to define independent transformation for the connection, reducing to the standard formula in case the connection is Levi-Civita with respect to the metric. In my presentation, I shall present a scalar-tensor theory taking into account such transformation, called 'generalized almost-geodesic mapping’, and discuss properties of the solution to the field equation for the connection. The theory will be analysed in both the Einstein and the Jordan frame. I will also introduce invariant quantities, whose functional form remains unchanged irrespective of the conformal frame, and show how they can be applied to analysis of possible equivalence between F(R) and scalar-tensor theories of gravity in the Palatini formalism.

Data: 08.11.2018
Miejsce: Sala 422 14:15
Temat: Positive operators and entanglement detection
Osoba: Piotr Kopszak
Opis: Quantum entanglement is one of the most important phenomenon in quantum physics. It is interesting from the conceptual point of view, as well as very important in many applications. There are several methods of detecting and classifying entanglement. In my presentation I will concentrate on special observables, namely entanglement witnesses. I will present connection between them and linear operators that are positive, but not completely positive. and recent advances in describing new classes of such operators.

Data: 25.10.2018
Miejsce: Sala 422 14:15
Temat: Functional Schrödinger Picture and Wheeler-DeWitt Equation
Osoba: Lennart Brocki
Opis: In quantum field theory one usually employs the Fock basis to represent the eigenstates of the Hamiltonian, but there exists, in full analogy to quantum mechanics, a functional Schrödinger picture in field theories. I will give a brief overview of this formalism and also present some notions of canonical quantum gravity, which is one of its main applications. In this context I will speak about the quantization of constrained systems and the Wheeler-DeWitt equation.

Data: 11.10.2018
Miejsce: Sala 422 14:15
Temat: Relacyjne i nierelacyjne bazy i modele danych – porównanie na przykładzie bazy grafowej
Osoba: mgr Przemysław Socha
Opis: Podczas pierwszego wystąpienia przedstawię wyniki z mojej pracy magisterskiej, która dotyczyła porównania modelu relacyjnego i grafowego w kontekście wydajności tworzonej bazy danych. Dodatkowo opowiem o pozostałych popularnych nierelacyjnych systemach przetwarzania danych.

Data: 24.05.2018
Miejsce: Sala 420 14:15
Temat: How to give a good seminar
Osoba: dr hab. Chihiro Sasaki
Opis: I will give a presentation on soft skills, focusing on the skills how to give a good seminar.

Data: 12.04.2018
Miejsce: Sala 422 14:15
Temat: Colour Evolution of Low-Mas X-ray Binary 4U 1636-536
Osoba: Udita Shukla
Opis: The work deals with the colour evolution of neutron star low-mass X-ray binary 4U 1636-536 by constructing light curves. 1,476 light curves were extracted corresponding to the energy bands of (2-60) keV, (2.5-5.7) keV and (7.8-16.4) keV. The light curve shows a rough quasi-periodicity of ~ 40-46 days in terms of a clear count rate oscillation. Hardness ratio is found to vary in more or less periodic fashion but being constantly out of phase with the light curve. The hardness-Intensity Diagram has most of the observations clustered in the softer region of the plot corresponding to the banana state whereas, the harder positions or the island state appear as a nearly constant band in the vicinity of 0.5 (Hardness Ratio). Spectra extracted for the energy range (3.0 – 50.0) keV, were fit with a compound model comprising of photo-electric absorption, ‘phabs’, and Blackbody, Gaussian and Comptonizing (high-energy) cut-off. The Gaussian line rises up at ~ 6 keV in the fits. The fit is seen to support the so-called ‘Western’ model (White et al. 1988) comprising of a Comptonizing Accretion Disk Corona (ADC) and the neutron star emitting as a Blackbody. The Blackbody temperature of the neutron star centres around 1 keV to 2 keV, while the (Blackbody) radius broadens as we move from the island to the banana state reaching ~ 1 km, implying that the blackbody emission is from a restricted part of the neutron star.

Data: 29.03.2018
Miejsce: Sala 422 14:15
Temat: CFD-DEM methods for simulations of proppants transport in hydraulic fractures
Osoba: Jakub Poła
Opis: As part of my speech, I will present all the issues that I dealt with during the ShaleMech project. I will discuss the concept of CFD-DEM method in approach of resolved and unresolved, the way to take into account the effect of particle rotation in simulation and the model of particle collision correction in two-phase systems. In the final part, I will present applications of the CFD-DEM method for simulation of proppants transport in various systems and the use of the CFD-DEM method for studying porous systems.

Data: 15.03.2018
Miejsce: Sala 422 14:15
Temat: Polarization Transfer in Weak Pion Production off the Nucleon
Osoba: Beata Kowal
Opis: During my presentation I will present results of the investigation of the polarization transfer observables in the single pion production in neutrino-nucleon scattering and methods for obtaining them. My presentation bases on the papers PhysRevD.97.013001 and APhysPolB.48.2219.

Data: 01.03.2018
Miejsce: Sala 422 14:15
Temat: On Strangeness in NA61/SHINE
Osoba: Maciej Lewicki
Opis: NA61/SHINE is a fixed target experiment at the CERN Super-Proton-Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and to study the properties of the onset of deconfinement. In order to reach these goals, a study of hadron production properties is performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a function of collision energy and size of the colliding nuclei. One of the predicted signatures of the onset of deconfinement are substantial changes in dynamics of strangeness production. In this talk, I will give an overview of statistical and dynamical models of strangeness production in the vicinity of phase transition. Predictions of the models will be compared with available results on heavy-ions collisions, including new results on intermediate mass systems from NA61/SHINE.

Data: 18.01.2018
Miejsce: Sala 422 14:15
Temat: Polyakov loop fluctuations in the presence of external fields
Osoba: Michał Szymański
Opis: One of important goals of high energy physics is to understand the deconfinement – liberation of quarks from hadrons under extreme temperatures and densities. For systems with small net quark number density many insights are provided by first-principle lattice QCD calculations. Especially important are results on Polyakov loop which plays the role of an order parameter of deconfinement in the limit of infinitely heavy quarks and serves as an approximate order parameter in systems with dynamical quarks. In this talk I will focus on ratios of Polyakov loop susceptibilities and argue why these quantities may be considered as excellent probes of deconfinement. I will also discuss an effective model which captures trends in recent lattice QCD data on these ratios.

Data: 04.01.2018
Miejsce: Sala 422 14:15
Temat: Vector-interaction-enhanced bag model
Osoba: Mateusz Cierniak
Opis: For studies of quark matter in astrophysical scenarios the thermodynamic bag model (tdBag) is commonly employed. This model approximates the effect of quark confinement, but it lacks other important properties of Quantum Chromodynamics. The vector-interaction-enhanced bag model (vBAG) improves the tdBAG approach by taking into account dynamical chiral symmetry breaking and repulsive vector interactions. The latter is of particular importance to studies of dense matter in beta-equilibrium in order to explain the 2 solar mass maximum mass constraint for neutron stars. Another particular feature of vBag is the determination of the deconfinement bag constant (Bdc) from a given hadronic equation of state (EoS) in order to ensure that chiral and deconfinement transitions coincide. The model can be derived from the QCD based framework of Dyson-Schwinger equations by assuming a simple quark-quark contact interaction. This work will focus on the resulting neutron star equations of state.