Holographic Chiral Magnetic Conductivity

TL;DR

This paper uses holographic models to compute the time-dependent chiral magnetic conductivity in strongly coupled regimes, providing insights relevant for quark-gluon plasma studies.

Contribution

It offers the first holographic computations of chiral magnetic conductivity in time-dependent settings using two different models, including back-reacted Einstein-Maxwell and Sakai-Sugimoto.

Findings

Chiral magnetic conductivity is influenced by the axial anomaly via Chern-Simons terms.

Results are consistent with weak-coupling calculations in certain regimes.

The models reveal the role of back-reaction in the conductivity behavior.

Abstract

We present holographic computations of the time-dependent chiral magnetic conductivity in the framework of gauge/gravity correspondence. Chiral magnetic effect is a phenomenon where an electromagnetic current parallel to an applied magnetic field is induced in the presence of a finite axial chemical potential. Motivated by a recent weak-coupling perturbative QCD calculation, our aim is to provide a couple of complementary computations for strongly coupled regime which might be relevant for strongly coupled RHIC plasma. We take two prototypical holographic set-ups for computing chiral magnetic conductivity; the first model is Einstein gravity with U(1)_L X U(1)_R Maxwell theory, and our second set-up is based on the Sakai-Sugimoto model in a deconfined and chiral symmetry restored phase. While the former takes into account full back-reaction while the latter not, the common feature is an important role played by the appropriate 5-dimensional Chern-Simons term corresponding to the 4-dimensional axial anomaly.