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

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 squared $c_s^2(T)$. 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.