Fluid/gravity model for the chiral magnetic effect

TL;DR

This work addresses how chiral magnetic and vortical effects emerge in a strongly coupled plasma with anomalous U(1) currents by constructing a holographic dual using the three-charge STU gravity model. It employs fluid-gravity duality with external fields to derive first-order anomaly-induced transport coefficients and demonstrates that a two-charge reduction yields the CME and CVE with explicit holographic corrections. The study provides a consistent holographic realization of anomaly-driven transport, matching hydrodynamic predictions and extending to a time-dependent, expanding-plasma scenario. This framework advances the understanding of CME/CVE in heavy-ion collisions and related plasmas by connecting hydrodynamic anomalies to concrete gravitational duals and their gradient expansions.

Abstract

We consider the STU model as a gravity dual of a strongly-coupled plasma with multiple anomalous U(1) currents. In the bulk we add additional background gauge fields to include the effects of external electric and magnetic fields on the plasma. Reducing the number of chemical potentials in the STU model to two and interpreting them as quark and chiral chemical potential, we obtain a holographic description of the chiral magnetic and chiral vortical effects (CME and CVE) in relativistic heavy ion collisions. These effects formally appear as first-order transport coefficients in the electromagnetic current. We compute these coefficients from our model using fluid/gravity duality. We also find analogous effects in the axial current. Finally, we briefly discuss a variant of our model, in which the CME/CVE is realized in the late-time dynamics of an expanding plasma.