Holographic chiral currents in a magnetic field

TL;DR

This paper uses a holographic model to compute magnetic-field-induced axial and vector currents in a QCD-like setting, revealing an axial current consistent with prior results and a null vector current, contrasting weak-coupling predictions.

Contribution

It provides a holographic calculation of chiral currents in a magnetic field within the Sakai-Sugimoto model, incorporating the axial anomaly.

Findings

Axial current aligns with previous theoretical studies.

Vector current vanishes, differing from weak-coupling results.

Results support the holographic approach to chiral magnetic phenomena.

Abstract

In the presence of a quark chemical potential, a magnetic field induces an axial current in the direction of the magnetic field. We compute this current in the Sakai-Sugimoto model, a holographic model which, in a certain limit, is dual to large-N_c QCD. We also compute the analogous vector current, for which an axial chemical potential is formally introduced. This vector current can potentially be observed via charge separation in heavy-ion collisions. After implementing the correct axial anomaly in the Sakai-Sugimoto model we find an axial current in accordance with previous studies and a vanishing vector current, in apparent contrast to previous weak-coupling calculations.