Chiral symmetry breaking and restoration by helical magnetic fields in AdS/CFT

TL;DR

This paper investigates how helical magnetic fields influence chiral symmetry breaking and restoration in a holographic QCD model, revealing that such fields can restore symmetry and induce chiral magnetic effects.

Contribution

It introduces the effects of helical magnetic fields on chiral symmetry within the AdS/QCD framework, highlighting their role in symmetry restoration and current generation.

Findings

Helical magnetic fields can restore chiral symmetry broken by uniform fields.

A chiral magnetic effect-like current is observed parallel to the magnetic field.

Helical fields are less effective in removing first order phase transitions in massive cases.

Abstract

We study the effects of helical magnetic fields on chiral symmetry breaking within the AdS/QCD framework using the D3/D7-brane model. By analyzing the brane embeddings, we obtain three types of massless solutions, corresponding to three phases with different behavior in the dual field theory. From the study of quark condensates, free energy, and electric currents, we find that helical magnetic fields can counteract uniform-field-induced symmetry breaking, driving the system towards symmetry restoration. We also find an effect analog to the chiral magnetic effect whereby the current is parallel to the magnetic field. We further study the massive case, and find that the helical configuration is less effective in erasing the first order phase transition that is present in the case of a constant magnetic field.