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

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.