Generalized Entropy and Transport Coefficients of Hadronic Matter

We use the generalized entropy four-current of the Muller-Israel-Stewart (MIS) theory of relativistic dissipative fluids to obtain information about fluctuations around equilibrium. This allows one to compute the non-classical coefficients of the entropy 4-flux in terms of the equilibrium distribution functions. The Green-Kubo formulae are used to compute the classical or standard transport coefficients from the fluctuations of entropy due to dissipative fluxes.Comment: 8 pages, Zimanyi 75 Memorial Workshop on Hadronic and Quark Matter, Budapest, Hungary, 200

Suppression of elliptic flow in a minimally viscous quark-gluon plasma

We compute the time evolution of elliptic flow in non-central relativistic heavy-ion collisions, using a (2+1)-dimensional code with longitudinal boost-invariance to simulate viscous fluid dynamics in the causal Israel-Stewart formulation. We show that even ``minimal'' shear viscosity eta/s=hbar/(4pi) leads to a large reduction of elliptic flow compared to ideal fluid dynamics, raising questions about the interpretation of recent experimental data from the Relativistic Heavy Ion Collider.Comment: 5 pages, incl. 4 figures. Fig.2 redrawn, several footnotes and references added. This version accepted by Physics Letters

Dissipative Relativistic Fluid Dynamics for Nuclear Collisions

In the context of the M\"uller-Israel-Stewart second-order theory for dissipative fluids due to Grad, we analyze the effects of thermal conduction and viscosity in heavy ion collisions. We contrast the results to those of the first-order theory due to Eckart and to Landau and Lifshitz and to those of perfect (ideal) fluid due to Euler. We study the energy density and entropy density evolution of a pion gas produced in the heavy ion collisions. The truncated version of the second-order theory is used to find the dissipative quantities.Comment: 10 pages, 4 figures, Proceedings of the 17th Winter Workshop on Nuclear Dynamics, Park City, Utah, March 10-17, 200

Equation of State and Transport Coefficients of Relativistic Nuclear Matter

In order to evaluate qualitatively the space-time evolution of hot and dense nuclear matter the underlying equation of state and transport coefficients must be known. In this study a specific equation of state is studied: the pion gas. The classical or standard transport coefficients, namely the bulk viscosity, shear viscsoity and thermal conductivity are devided by the relaxation times for the corresponding dissipative fluxes and then studied as functions of mass to temperature ratio.Comment: 5 pages, Strange Quark Matter 2007, Levoca, Slovaki

Viscous hydrodynamics

We study the role of viscosity in the early stages of relativistic heavy ion collisions. We investigate the role of viscosity on the chemical equilibration of a parton gas. In the presence of viscosity the lifetime of the system is increased. The temperature as well as the parton fugacities evolve more slowly compared to the ideal fluid dynamics.Comment: 4 pages, Strange Quark Matter 2004, Cape Town, South Afric

Momentum Broadening in an Anisotropic Plasma

The rates governing momentum broadening in a quark-gluon plasma with a momentum anisotropy are calculated to leading-log order for a heavy quark using kinetic theory. It is shown how the problematic singularity for these rates at leading-oder is lifted by next-to-leading order gluon self-energy corrections to give a finite contribution to the leading-log result. The resulting rates are shown to lead to larger momentum broadening along the beam axis than in the transverse plane, which is consistent with recent STAR results. This might indicate that the quark-gluon-plasma at RHIC is not in equilibrium.Comment: 14 pages, 2 figures, uses revtex4; see source for numerics; v2: typos corrected, note added in appendix, matches published versio