A holographic model of deconfinement and chiral symmetry restoration

TL;DR

This paper explores the finite temperature phase transitions in a holographic model of QCD, revealing how deconfinement and chiral symmetry restoration depend on parameters like quark separation and temperature, with all transitions being first order.

Contribution

It provides a detailed analysis of the phase structure of the Sakai-Sugimoto model at finite temperature, highlighting the dependence of chiral symmetry restoration on quark separation and temperature.

Findings

Deconfinement occurs at T_d = 1 / 2π R.

Chiral symmetry is restored at T = 0.154 / L for L < L_c.

An intermediate phase exists for L > L_c with deconfined but broken chiral symmetry.

Abstract

We analyze the finite temperature behavior of the Sakai-Sugimoto model, which is a holographic dual of a theory which spontaneously breaks a U(N_f)_L x U(N_f)_R chiral flavor symmetry at zero temperature. The theory involved is a 4+1 dimensional supersymmetric SU(N_c) gauge theory compactified on a circle of radius R with anti-periodic boundary conditions for fermions, coupled to N_f left-handed quarks and N_f right-handed quarks which are localized at different points on the compact circle (separated by a distance L). In the supergravity limit which we analyze (corresponding in particular to the large N_c limit of the gauge theory), the theory undergoes a deconfinement phase transition at a temperature T_d = 1 / 2 \pi R. For quark separations obeying L > L_c = 0.97 * R the chiral symmetry is restored at this temperature, but for L < L_c = 0.97 * R there is an intermediate phase which is deconfined with broken chiral symmetry, and the chiral symmetry is restored at T = 0.154 / L. All of these phase transitions are of first order.