Anatomy of chiral magnetic effect in and out of equilibrium

TL;DR

This paper introduces a new magnetization current contribution to the chiral magnetic conductivity at finite frequencies, enabling a quantitative match with field-theoretic AC responses and highlighting potential tunability in condensed matter systems.

Contribution

It identifies the magnetization current as a key factor in the AC chiral magnetic response and demonstrates its calculation within kinetic theory for QCD plasma.

Findings

Magnetization current accounts for finite-frequency chiral magnetic conductivity.

The approach matches known field-theoretic AC responses.

Potential for tuning in condensed matter due to variable g-factor.

Abstract

We identify a new contribution to the chiral magnetic conductivity at finite frequencies -- the magnetization current. This allows to quantitatively reproduce the known field-theoretic time-dependent (AC) chiral magnetic response in terms of kinetic theory. We evaluate the corresponding AC chiral magnetic conductivity in two flavor QCD plasma at weak coupling. The magnetization current results from the spin response of chiral quasiparticles to magnetic field, and is thus proportional to the quasiparticle's $g$-factor. In condensed matter systems, where the chiral quasi-particles are emergent and the $g$-factor can significantly differ from 2, this opens the possibility to tune the AC chiral magnetic response.