Inverse Magnetic Catalysis in the Soft-Wall Model of AdS/QCD

TL;DR

This paper investigates how magnetic fields influence chiral phase transitions within a modified soft-wall AdS/QCD model, revealing inverse magnetic catalysis where increasing magnetic fields lower the transition temperature.

Contribution

The study introduces a negative-positive dilaton profile in the soft-wall model and numerically demonstrates inverse magnetic catalysis effects on chiral symmetry restoration.

Findings

Chiral phase transition remains second order in the chiral limit at finite B.

Chiral condensate and transition temperature decrease with increasing magnetic field.

Inverse magnetic catalysis observed when finite quark mass effects are included.

Abstract

Magnetic effects on chiral phase transition have been investigated in a modified soft-wall AdS/QCD model, in which the dilaton field is taken to be negative at the ultraviolet region and positive at the infrared region as in Phys.Rev.D93(2016),101901 and JHEP1604(2016)036. The magnetic field is introduced into the background geometry by solving the Einstein-Maxwell system. After embedding the magnetized background geometry into the modified soft-wall model, the magnetic field dependent behavior of chiral condensate is worked out numerically. It is found that, in the chiral limit, the chiral phase transition remains as a second order at finite magnetic field $B$, while the symmetry restoration temperature and chiral condensate decrease with the increasing of magnetic field in small $B$ region. When including finite quark mass effect, the phase transition turns to be a crossover one, and the transition temperature still decreases with increasing magnetic field $B$ when $B$ is not very large. In this sense, inverse magnetic catalysis effect is observed in this modified soft-wall AdS/QCD model.