Transport coefficients for the hot quark-gluon plasma at finite chemical potential $μ_B$

Abstract

We calculate transport coefficients of the quark-gluon plasma (QGP) within the dynamical quasiparticle model (DQPM) by explicitly computing the parton interaction rates as a function of temperature $T$ and baryon chemical potential $μ_B$ on the basis of the DQPM couplings and partonic propagators. The latter are extracted from lattice QCD by matching the equation of state, entropy density and energy density at $μ_B$= 0. For baryon chemical potentials $0 \leq μ_B \leq 500 MeV$ we employ a scaling Ansatz for the effective coupling which was shown before to lead to thermodynamic consistent results in this range. We compute the ratio of the shear and bulk viscosities to the entropy density, i.e. $η/s$ and $ζ/s$, the electric conductivity $σ_0/T$ as well as the baryon diffusion coefficient $κ_B$ and compare to related approaches from the literature. We find that the ratios $η/s$ and $ζ/s$ as well as $σ_0/T$ are in accord with the results from lattice QCD at $μ_B$=0 and only weakly depend on the ratio $T/T_c(μ_B)$ where $T_c(μ_B)$ denotes the critical temperature at finite baryon chemical potential.