Data: 22.03.2019
Miejsce: Sala 422 10:30
Temat: Bose polarons in the trap
Osoba: Prof. Eiji Nakano (Kochi University, Japan)
Opis: Polaron originaly means the conducting electron dressed by phonon cloud in a dielectric crystal, described as a quasiparticle with a medium dependent effective mass. Recently a cold-atomic many body system mimics the polaron, where an impurity atom immersed in atomic BEC is dressed by Bogoliubov phonon cloud to be a 'Bose polaron’. The Bose polaron has been observed in some experiments in a very controlled way: dimensionality, interaction between impurity and BEC atoms, and property of BEC can be designed almost at will. Theoretical works so far entirely assumed uniform systems, although the experiments were done in traps.The local density approximation is not an adequate tool for detailed description of polaron structure, because the impurity itself causes inhomogeneity. So, we directly calculate properties of Bose polarons in trap potentials, taking care of the angular momentum conservation, instead of the momentum conservation in uniform systems.

Data: 22.02.2019
Miejsce: Sala 422 10:30
Temat: Using a variational method to study nuclear matter, hyper nuclear matter and neutron stars
Osoba: Mahboubeh Shahrbaf (University of Teheran, Iran)
Opis:We investigate the equation of state of nuclear matter, hyper nuclear matter and compact stars within our variational method. Chemical potentials of nucleons in asymmetric nuclear matter are calculated in a completely self-consistent manner, using the lowest order constrained variational (LOCV) method. Employing different nucleon–nucleon potentials, threshold density of free hyperons formation and the maximum mass of hypernuclear star are determined. Furthermore, the particles fraction in beta stable and charge neutral matter is calculated as well. The effects of three-body force (TBF) on the onset of hyperons, particle composition and maximum mass of the star are discussed. On the basis of this method which is reformulated by using two-body central potentials for Λ-N and Λ-Λ interaction that were determined so as to reproduce the experimental data on single- and double-Λ hypernuclei, the equation of state of hyper nuclear matter is found for the first time in this method. Calculation of correlation functions for N-Y and Y-Y interaction for each JLSTMT-channel is done for the first time as well.

Data: 11.01.2019
Miejsce: Sala 422 10:30
Temat: Modelling anisotropic magnetised White Dwarfs with $gamma$ metric
Osoba: Diana Alvear Terrero (IFT)
Opis:Magnetic fields introduce an anisotropy in compact stars’ equations of state by splitting the pressure into two components, one parallel and the other perpendicular to the magnetic field. This suggests the necessity of using structure equations accounting for the axial symmetry of the magnetised system. We consider an axially symmetric metric in spherical coordinates, the $gamma$-metric, and construct a system of equations to describe the structure of spheroidal compact objects. In this way, we connect the geometrical parameter $gamma$ linked to the spheroid’s radii, with the source of the anisotropy. So, the model relates the shape of the compact object to the physics thatdetermines the properties of the composing matter. To illustrate how our structure equations work, we obtain the mass-radii solutions for magnetised White Dwarfs.

Data: 14.12.2018
Miejsce: Sala 422 10:30
Temat: Shear viscosity of the QGP from the relaxation time approximation within the quasiparticle model
Osoba: Valeriya Mykhaylova (IFT)
Opis:It is known that the quark-gluon plasma is well described in terms of perfect fluid dynamics [1]. Besides, it is a common fact that there is nothing perfect in the world (although one should try – LT 🙂 ). Therefore, one needs to include dissipative processes, which are described by transport coefficients, into the QGP dynamics. I will present the shear viscosity obtained from the relaxation time approximation of the Boltzmann equation. The calculations are performed within the quasiparticle model, where dynamical quark and gluon masses depend on the lattice data [2]. [1] E. Shuryak, Prog. Part. Nucl. Phys. 53 (2004) [2] S. Borsanyi et al., Phys. Lett. B 370 (2014) 99-104

Data: 07.12.2018
Miejsce: Sala 422 10:30
Temat: NJL model in strong magnetic field
Osoba: Michał Szymański (IFT)
Opis:Strong magnetic fields are expected to be present in non-central heavy ion collisions and in the interior of compact stars. Lattice QCD simulations show that deconfinement and chiral phase transition are affected by the presence of magnetic field. I will discuss properties of the latter using the Nambu-Jona-Lasinio model. Effect of th lowest Landau level will be also examined.

Data: 30.11.2018
Miejsce: Sala 422 10:30
Temat: CANCELLED Pion-gluon interaction through Boltzmann equation
Osoba: Łukasz Juchnowski (IFT)
Opis:CANCELLED We study the particle production in the early stage of the ultrarelativistic heavy-ion collisions. To this end the Boltzmann kinetic equations for gluons and pions with elastic rescattering are considered together with a simple model for the parton-hadron conversion process (hadronisation). It is shown that the overpopolation of the gluon phase space in the initial state leads to an intermediate stage of Bose enhancement in the low momentum gluon sector that is reflected in the final distribution function of pions, which is very similar to the experimental finding of a low-momentum pion enhancement in the ALICE experiment at CERN LHC. In this talk I will present state of the project and difficulties we are facing.

Data: 23.11.2018
Miejsce: Sala 422 10:30
Temat: Dyson–Schwinger equations in astrophysics
Osoba: Mateusz Cierniak (IFT)
Opis:We study the properties of dense, strongly interacting matter using the Dyson-Schwinger equation (DSE) formalism. Within this formalism, by using particular sets of truncations, one can self consistently derive quark properties in–medium. No first principle calculations of QCD are able to provide reliable results for such conditions. The effective models used instead, most notably the Nambu–Jona-Lasino and tdBag models can be understood as limiting cases of the DSE. Furthermore, the formalism provides a straightforward method for extending the derived models to finite temperature and isospin asymmetry, making them useful for studies of astrophysical phenomena such as core–collapse supernovas, neutron star mergers and in general to derive neutron star properties. We will focus on the current state of–the–art in DSE studies of these phenomena.

Data: 19.10.2018
Miejsce: Sala 422 10:30
Temat: (First steps) towards a unified quark-hadron matter equation of state
Osoba: Niels-Uwe Bastian (IFT)
Opis:We consider a cluster expansion for strongly correlated quark matter where the clusters are baryons with spectral properties that are described within the generalized Beth-Uhlenbeck approach by a medium dependent phase shift. We employ a simple ansatz for the phase shift which fulfils the Levinson theorem by describing an on-shell bound state with an effective mass and models the continuum by an anti-bound state located at the mass of the three quark threshold. The quark and baryon interactions are accounted for by the coupling to scalar and vector meson mean fields modelled by density functionals. At increasing density and temperature, due to the different medium dependence of quark and baryon masses, the Mott dissociation of baryons occurs and the nuclear clusters contributions to the thermodynamics vanish. It is demonstrated on this simple example that this unified approach to quark-nuclear matter is capable of describing crossover as well as first order phase transition behaviour in the phase diagram with a critical endpoint.

Data: 12.10.2018
Miejsce: Sala 422 10:30
Temat: Quark Pauli blocking in hadronic matter
Osoba: David Blaschke (IFT, UWr), Alexandra Friesen (JINR Dubna).
Opis:We show that the Phi-derivable formulation of the cluster virial expansion for quark matter contains the quark Pauli blocking effect in the lowest order expansion with respect to the backreaction of hadrons on the quark dynamics. We discuss this effect for the pion gas and for nuclear matter within a nonrelativistic potential model and estimate its enhancement by partial chiral symmetry restoration in dense matter.

Data: 05.10.2018
Miejsce: Sala 422 10:30
Temat: NA61/SHINE news – preliminary signatures of deconfinement and clustering effects in the hot dense hadronic matter
Osoba: Maciej Lewicki (IFT)
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 toreach 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. In this talk, the newest preliminary results on identified hadron spectra produced in Ar+Sc and Be+Be collisions at six beam momenta (13A, 19A, 30A, 40A, 75A and 150A GeV/c) will be shown. The kinematic distributions and measured multiplicities of identified hadrons will be compared with NA61/SHINE and NA49 p+p and Pb+Pb results, as well as with available world data.

Data: 07.09.2018
Miejsce: Sala 422 10:30
Temat: Third family of compact stars with a nonlocal chiral quark model EoS
Osoba: Prof. David Blaschke (UWr & JINR)
Opis: We show that the quark matter equation of state (EoS) obtained within a color superconducting chiral quark model with nonlocal, covariant interactions does not allow for obtaining a third family of hybrid compact stars unless one invokes a density dependence of the vector meson coupling and a density-dependent bag pressure. These density dependences are of the model parameters are obtained from a matching with the string-flip model EoS [Kaltenborn et al., PRD (2017)] for three cases of the screening parameter alpha = 0.20, 0.24, and 0.30. Modern constraints from compact star phenomenology are discussed for these EoS.

Data: 29.06.2018
Miejsce: Sala 422 10:30
Temat: Probing QGP properties with strangeness
Osoba: Jan Rafelski, Department of Physics, The University of Arizona, Tucson
Opis: Beginning with the CERN SPS experiments 30 years ago we search for the understanding of how energy becomes matter, that is we study the hadronization of primordial phase of matter, quark-gluon plasma. Today the ALICE is the experiment at the CERN LHC build predominantly to study this process. The key information is derived in study of multistrange hadrons which carry information both, about the process of matter production (hadronization) E => mc^2, as well as about earlier stages when entropy and strangeness are produced. Very recent results show that even a relatively small pp and pA collisions at the LHC energy-scale are creating the new quark-gluon plasma (QGP) phase of matter.

Data: 15.06.2018
Miejsce: Sala 422 10:30
Temat: Self-consistent viscous phase space distributions from kinetic theory
Osoba: Dr Denes Molnar (Purdue University, USA)
Opis: The main challenge is to describe how local phase space distributions are modified compared to their local equilibrium form in the presence of gradiens and dissipation in the system. In fact, an infinite class of phase space distributions can describe the same hydrodynamic fields. We advocate a self-consistent approach that obtains phase space corrections from relativistic kinetic theory. A both self-consistent shear viscous and bulk viscous phase space corrections calculated for a many component gas of hadrons will be presented and discussed how the corrections affect experimental observables.

Data: 11.05.2018
Miejsce: Sala 422 10:30 
Temat: Finite size effects, intermolecular forces and effective virial expansion
Osoba: Ludwik Turko (IFT)
Opis: A thermodynamically self-consistent model of quantum gas with the effective collective interaction will be presented

Data: 27.04.2018
Miejsce: Sala 428 10:15
Temat: Transport coefficients of Yang-Mills plasma
Osoba: Valeriya Mykhaylova (IFT)
Opis: OTHER LECTURE, OTHER SUBJECT – beyond this nothing has been changed 🙂 LT in 2 weeks In the relaxation time approximation, the ratio of the bulk to the shear viscosities is discussed. A recent study including the Gribov parameter exhibits that this ratio goes like what is predicted in the AdS/CFT approach, even at very high temperature. We aim for a better understanding of this result.

Data: 06.04.2018
Miejsce: Sala 422 10:30
Temat: Compact star tidal deformability constraints from the GW170817 event and their impact on the equation of state
Osoba: Dr David Alvarez-Castillo (JINR Dubna)
Opis: The method of estimation of tidal deformabilities of compact stars and present results for pure hadronic as well as hybrid stars that include the mass twins case will be presented. Then the recent GW170817 compact star tidal deformability constraints that serve to estimate radius values related to the stiffness of compact star matter will be analyzed.

Data: 23.03.2018
Miejsce: Sala 422 10:15
Temat: Non-equilibrium Charmonium dynamics in heavy-ion collisions
Osoba: Dr Gábor Balassa (Wigner Research Centre for Physics, Hungarian Academy of Sciences)
Opis: The masses of the low lying charmonium states, shifted downwards due to the second order Stark effect. In pbar Au collisions at 6−10 GeV we study their in-medium propagation.The time evolution of the spectral functions of these charmonium states are studied with a Boltzmann Uehling-Uhlenbeck (BUU) type transport model. The in medium mass shift of these states can be observed in the dilepton spectrum, therefore, by observing the dileptonic decay channel of these low lying charmonium states, especially for PSI(3686), one can gain information about the largeness of the gluon condensate in nuclear matter. The methods used to calculate the elementary cross sections with charmonium in the final states are also discussed.

Data: 09.01.2018
Miejsce: Sala 60 17:00
Temat: On Transitions in High Energy Nuclear Collisions; News from NA61/SHINE at CERN SPS
Osoba: UNUSUAL TIME and PLACE! Prof. Marek Gazdzicki (UJK Kielce and Frankfurt Univ.)
Opis: NA61/SHINE is a fixed target experiment at the CERN SPS. The main goals of the experiment is to discover the critical point of hadronic matter and to study the properties of the onset of deconfinemnt. Prof. Gazdzicki is the spokesperson of the NA61/SHINE Collaboration.