Bulk Viscosity of Hot Quark Plasma from Non-Equilibrium Statistical Operator

TL;DR

This paper calculates the bulk viscosity of a two-flavor quark plasma using the Nambu--Jona-Lasinio model and Kubo-Zubarev formalism, emphasizing the role of loop resummation near the Mott transition.

Contribution

It provides a detailed derivation of bulk viscosity with multiple conserved charges and numerical analysis near the Mott transition line, highlighting the importance of loop resummation.

Findings

Bulk viscosity is dominated by meson decay processes near the Mott line.

Loop resummation is crucial for accurate results.

Numerical results clarify dissipation mechanisms in quark plasma.

Abstract

We provide a discussion of the bulk viscosity of two-flavor quark plasma, described by the Nambu--Jona-Lasinio model, within the framework of Kubo-Zubarev formalism. This discussion, which is complementary to our earlier study, contains a new, detailed derivation of the bulk viscosity in the case of multiple conserved charges. We also provide some numerical details of the computation of the bulk viscosity close to the Mott transition line, where the dissipation is dominated by decays of mesons into quarks and their inverse processes. We close with a summary of our current understanding of this quantity, which stresses the importance of loop resummation for obtaining the qualitatively correct result near the Mott line.