Transport coefficients near chiral phase transition

TL;DR

This paper investigates how shear and bulk viscosities of a relativistic quark fluid behave near the chiral phase transition, using kinetic theory and the NJL model, to understand signatures of the critical end point.

Contribution

It provides a detailed analysis of transport coefficients near the chiral phase transition, incorporating in-medium effects and the influence of the phase transition order.

Findings

Shear and bulk viscosities show distinct behavior near the phase transition.

Viscosity changes are sensitive to the presence of the critical end point.

Transport coefficients can serve as probes for the phase transition characteristics.

Abstract

We analyze the transport properties of relativistic fluid composed of constituent quarks at finite temperature and density. We focus on the shear and bulk viscosities and study their behavior near chiral phase transition. We model the constituent quark interactions through the Nambu--Jona Lasinio Lagrangian. The transport coefficients are calculated within kinetic theory under relaxation time approximation including in--medium modification of quasi--particles dispersion relations. We quantify the influence of the order of chiral phase transition and the critical end point on dissipative phenomena in such a medium. Considering the changes of shear and bulk viscosities along the phase boundary we discuss their sensitivity to probe the existence of the critical end point.