Holographic Description of the Phase Diagram of a Chiral Symmetry Breaking Gauge Theory

TL;DR

This paper uses holographic duality to analyze the phase diagram of a gauge theory with chiral symmetry breaking, revealing the nature of phase transitions and critical points under varying temperature, chemical potential, and quark mass.

Contribution

It provides a detailed holographic study of the phase structure and critical phenomena in a chiral symmetry breaking gauge theory with magnetic field effects.

Findings

Identification of first and second order phase transitions.

Locating tri-critical and critical points in the phase diagram.

Effect of quark mass on the transition types and critical points.

Abstract

The large N_c N=4 gauge theory with quenched N=2 quark matter in the presence of a magnetic field displays chiral symmetry breaking. We study the temperature and chemical potential dependence of this theory using its gravity dual (based on the D3/D7 brane system). With massless quarks, at zero chemical potential, the theory displays a first order thermal transition where chiral symmetry is restored and simultaneously the mesons of the theory melt. At zero temperature, these transitions with chemical potential are second order and occur at different chemical potential values. Between the three there are two tri-critical points, the positions of which we identify. At finite quark mass the second order transition for chiral symmetry becomes a cross over and there is a critical point at the end of the first order transition, while the meson melting transition remains similar to the massless quark case. We track the movement of the critical points as the mass is raised relative to the magnetic field.