The RG flow of Nambu--Jona-Lasinio model at finite temperature and density

TL;DR

This paper investigates the phase structure of the Nambu--Jona-Lasinio model at finite temperature and density using the functional renormalization group, revealing how quantum corrections influence the chiral phase boundary, especially at low temperatures and high densities.

Contribution

It introduces an analysis of the NJL model's RG flows at finite temperature and density, including the effects of large-N non-leading terms on the phase boundary.

Findings

Large-N non-leading terms cause singularities at the Fermi surface.

Quantum corrections significantly affect the phase boundary at low temperature and high density.

The study provides a detailed RG flow analysis of the NJL model under these conditions.

Abstract

We study the Nambu--Jona-Lasinio model at finite temperature and finite density by using the functional renormalization group. The RG flows of the four-fermi coupling constant in the NJL model are investigated. We obtain the chiral phase boundary in cases of the large-$N$ leading approximation and an improved approximation. The large-$N$ non-leading term at the vanishing temperature has a singularity at the fermi surface. We show that the quantum corrections by the large-$N$ non-leading term largely influence the phase boundary at the low temperature and high density region.