Nonlinear response of the chiral magnetic effect in the D3/D7 holographic model

TL;DR

This paper explores the highly nonlinear behavior of the chiral magnetic effect in a holographic D3/D7 model, revealing multi-valued current responses and stability conditions near phase transitions.

Contribution

It demonstrates the nonlinear current-magnetic field relationship and analyzes phase stability, advancing understanding of chiral transport in holographic gauge theories.

Findings

Chiral magnetic current shows multi-valued dependence on magnetic field.

Presence of axial chemical potential and magnetic field stabilizes the system.

Near phase boundary, the system exhibits highly nonlinear response characteristics.

Abstract

We investigate the nonlinear response of the chiral magnetic current to an external magnetic field in a holographic setup. Using the D3/D7 brane system, where the chiral magnetic effect (CME) can be realized by considering rotating probe D7-branes, corresponding to introducing an axial chemical potential, we analyze the current-magnetic field relation beyond the linear regime. Focusing on the vicinity of the phase boundary between the insulating phase and the CME phase, we find that the chiral magnetic current exhibits a multi-valued dependence on the magnetic field, indicating a highly nonlinear response characteristic of this model. We further study the dynamical stability of the insulating phase near the transition point, and show that the presence of both an axial chemical potential and an external magnetic field cooperatively stabilize the system. Our results clarify the interplay between the axial chemical potential and the magnetic field in determining the phase structure and stability of the system, and reveal new nonlinear aspects of chiral transport in holographic gauge theories.