Phase structures of strong coupling lattice QCD with overlap fermions at finite temperature and chemical potential

TL;DR

This paper investigates the phase structure of lattice QCD with overlap fermions at finite temperature and chemical potential, revealing a tricritical point separating different chiral phase transition lines in the strong coupling limit.

Contribution

It is the first study to analyze lattice QCD with overlap fermions at finite T and μ, deriving the effective free energy in the strong coupling limit using mean field approximation.

Findings

Identification of a tricritical point in the (μ,T) plane.

Existence of second order chiral transition at small μ and large T.

Presence of first order chiral transition at large μ and small T.

Abstract

We perform the first study of lattice QCD with overlap fermions at finite temperature $T$ and chemical potential $\mu$. We start from the Taylor expanded overlap fermion action, and derive in the strong coupling limit the effective free energy by mean field approximation. On the ($\mu,T$) plane and in the chiral limit, there is a tricritical point, separating the second order chiral phase transition line at small $\mu$ and large $T$, and first order chiral phase transition line at large $\mu$ and small $T$.