Münster 2011 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 49: Schwerionenkollisionen und QCD Phasen VI
HK 49.3: Vortrag
Donnerstag, 24. März 2011, 15:00–15:15, HS AP
Transport properties of the Quark-Gluon Plasma from a virial expansion — •Stefano Mattiello and Wolfgang Cassing — Institut für Theoretische Physik, Universität Giessen, Ger many
One of the most striking results coming from RHIC heavy-ion collisions is the observation that the quark-gluon plasma (QGP) created in ultrarelativistic Au + Au collisions behaves like an almost ideal liquid rather than a gas of quarks and gluons. Therefore a dynamic calculation of the transport properties as the shear viscosity η and the bulk viscosity ζ is desirable. In the quark-gluon plasma phase we calculate the shear and the bulk viscosity within a virial expansion approach. We focus on the ratio of η to the entropy density s, i.e. η/s and in the competition between shear and bulk viscosity near the critical temperature Tc. We derive a realistic equation of state using a virial expansion approach which allows to include the interactions between the partons in the deconfined phase and to evaluate the corrections to a single-particle partition function. Our numerical results give a ratio η/s≈ 0.1 at the critical temperature Tc, which is very close to the theoretical bound of 1/(4π). Furthermore, for temperatures T≤ 1.8 Tc the ratio η/s is in the range of the present experimental estimates 0.1−0.3 at RHIC and we observe a pronounced minimum of η/s close to the critical temperature Tc. Additionally, the systematic calculation of the bulk viscosity shows that its contribution is negligible in comparison to η. Finally, we discuss their application to dissipative hydrodynamical calculations.
This work is supported by DFG.