Thermoelectric coefficients of two-flavor quark matter from the Kubo formalism

TL;DR

This paper calculates thermoelectric coefficients of two-flavor quark matter using the Kubo formalism and NJL model, revealing their temperature and chemical potential dependence and estimating electric fields in heavy-ion collisions.

Contribution

It introduces a detailed calculation of thermoelectric coefficients in quark matter using the Kubo formalism and NJL model, incorporating spectral functions and thermal field theory techniques.

Findings

Thermoelectric coefficients increase linearly with temperature.

Coefficients decrease as chemical potential increases.

Electric fields generated can be significant in heavy-ion collisions.

Abstract

The hot quark matter created in heavy-ion collision experiments can exhibit strong temperature and chemical-potential gradients, which in turn can generate electric fields through thermoelectric effects. In this work, we investigate two relevant thermoelectric coefficients -- the thermopower (Seebeck coefficient) and the Thomson coefficient -- of two-flavor quark matter using the Kubo formalism and the Nambu--Jona-Lasinio model as an effective description of dense, finite-temperature QCD. The required two-point equilibrium correlation functions are evaluated using the Matsubara formalism of thermal field theory, applying a 1/Nc expansion to the relevant multi-loop Feynman diagrams. We employ previously derived quark spectral functions obtained from one--meson-exchange diagrams above the Mott transition temperature. Our numerical results show that both thermoelectric coefficients increase approximately linearly with temperature and decrease with increasing chemical potential. We also estimate the magnitude of the electric fields that can be generated in heavy-ion collisions by thermal gradients via the Seebeck effect.