Transport coefficients of chiral fluid dynamics using low-energy effective models

TL;DR

This paper calculates the first-order transport coefficients, including viscosities, of a chiral fluid with temperature-dependent quasiparticle masses using an effective kinetic theory and models like the linear sigma and NJL models.

Contribution

It introduces a method to compute transport coefficients in chiral fluids with temperature-dependent masses using a simplified kinetic theory approach.

Findings

Calculated bulk and shear viscosities for chiral models.

Demonstrated the use of relaxation time approximation in this context.

Provided quantitative estimates of transport coefficients from specific models.

Abstract

We investigate the first-order transport coefficients of a fluid made of quasiparticles with a temperature-dependent mass extracted from chiral models. We describe this system using an effective kinetic theory, given by the relativistic Boltzmann equation coupled to a temperature-dependent background field determined from the thermal masses. We then simplify the collision term using the relaxation time approximation and implement a Chapman-Enskog expansion to calculate all first-order transport coefficients. In particular, we compute the bulk and shear viscosities using thermal masses extracted from the linear sigma model coupled with constituent quarks and the NJL model.