Transport coefficients from the Nambu-Jona-Lasinio model for $SU(3)_f$

TL;DR

This paper computes transport coefficients and thermodynamic properties of the three-flavor Nambu-Jona-Lasinio model across temperatures, comparing results with other models and lattice QCD data to evaluate predictive accuracy.

Contribution

It provides a detailed calculation of transport coefficients within the NJL model and compares its predictive power with other models and lattice data.

Findings

NJL model has limited predictive power above the critical temperature.

PNJL and DQPM models better match lattice QCD data.

Transport coefficients vary significantly with temperature.

Abstract

We calculate the shear $\eta(T)$ and bulk viscosities $\zeta(T)$ as well as the electric conductivity $\sigma_e(T)$ and heat conductivity $\kappa(T)$ within the Nambu-Jona-Lasinio model for 3 flavors as a function of temperature as well as the entropy density $s(T)$, pressure $P(T)$ and speed of sound $c_s^2(T)$. We compare the results with other models such as the Polyakov-Nambu-Jona-Lasinio (PNJL) model and the dynamical quasiparticle model (DQPM) and confront these results with lattice QCD data whenever available. We find the NJL model to have a limited predictive power for the thermodynamic variables and various transport coefficients above the critical temperature whereas the PNJL model and DQPM show acceptable results for the quantities of interest.