Impact of different extended components of mean-field models on transport coefficients of quark matter and their causal aspects

Abstract

The role of different extensions of the Nambu-Jona-Lasinio (NJL) model-like addition of vector interaction, Polyakov loop extended version (PNJL), and the entangled PNJL (EPNJL) models on transport coefficients, such as shear viscosity, bulk viscosity, electrical conductivity, and thermal conductivity are critically analyzed. We have considered the standard expressions of transport coefficients, obtained in relaxation time approximation of kinetic theory. Influence of temperature-dependent order parameters on the temperature profile of transport coefficients are analyzed. The causal aspect of the massless case to these different extended components of mean-field models are also picturized where an approximated lower and upper bound are drawn for shear relaxation time.