Chiral phase transition and QCD phase diagram from AdS/QCD

TL;DR

This paper uses an improved soft-wall AdS/QCD model to explore the QCD phase diagram, revealing a crossover to first-order transition and the existence of a critical end point influenced by chemical potential effects.

Contribution

It introduces a refined AdS/QCD model capable of simultaneously capturing confinement, chiral symmetry breaking, and the phase transition behavior in the QCD phase diagram.

Findings

Critical end point exists in the phase diagram.

Crossover transition at low chemical potential.

First-order transition at higher chemical potential.

Abstract

We study the chemical potential effects on the chiral phase transition in a simply improved soft-wall AdS/QCD model, which can realize consistently the properties of linear confinement and spontaneous chiral symmetry breaking. The $\mu-T$ phase diagrams with both zero and physical quark masses have been obtained from this model. For the case of physical quark mass, the chiral transition has a crossover behavior at low chemical potential. With the increase of the chemical potential $\mu$, the critical temperature $T_c$ descends towards zero, and the crossover transition turns into a first-order one at some intermediate value of $\mu$, which implies that a critical end point naturally exists in this improved soft-wall model. All these features agree with our current perspective on the QCD phase diagram.