A comparative study on two different expressions of Bulk viscosity in the PNJL model

TL;DR

This paper compares two different expressions for bulk viscosity within the PNJL model, analyzing their numerical equivalence and discrepancies at zero and finite quark chemical potential, and observes a decreasing trend with temperature.

Contribution

It provides a comparative analysis of two bulk viscosity expressions in the PNJL model, extending previous studies to finite chemical potential.

Findings

Bulk viscosity decreases with temperature.

Numerical equivalence and discrepancies identified between the two expressions.

Extended analysis to finite quark chemical potential.

Abstract

We have gone through a comparative study on two different kind of bulk viscosity expressions by using a common dynamical model. The Polyakov-Nambu-Jona-Lasinio (PNJL) model in the realm of mean-field approximation, including up to eight quark interactions for 2+1 flavor quark matter, is treated for this common dynamics. We have probed the numerical equivalence as well as discrepancy of two different expressions for bulk viscosity at vanishing quark chemical potential. Our estimation of bulk viscosity to entropy density ratio follows a decreasing trend with temperature, which is observed in most of the earlier investigations. We have also extended our estimation for finite values of quark chemical potential.