Correction to the Chiral Magnetic Effect from axial-vector interaction

TL;DR

This paper explains the suppression of the chiral magnetic effect observed in lattice calculations using an NJL-type model, highlighting the role of axial-vector interactions and instanton effects, and discusses implications for the phase diagram.

Contribution

It introduces the impact of axial-vector interactions and instanton molecules on the CME within a QCD-inspired model, providing a nonperturbative perspective and predictions for lattice tests.

Findings

Suppression of CME due to axial-vector interactions.

Enhancement of CME by instanton-anti-instanton pairs.

Significant role of axial-vector interactions in the phase diagram.

Abstract

The recent lattice calculation at finite axial chemical potential suggests that the induced current density of the chiral magnetic effect (CME) is somehow suppressed comparing with the standard analytical formula. We show in a NJL-type model of QCD that such a suppression is a natural result when considering the influence of the attractive axial-vector interaction. We point out that the lattice result doesn't need to be quantitatively consistent with the analytical formula due to the chirality density-density correlation. We also investigate the nonperturbative effect of instanton molecules on the CME. Since an unconventional repulsive axial-vector interaction is induced, the CME will be enhanced significantly by the instanton-anti-instanton pairings. Such a prediction needs to be tested by more improved lattice simulations. We further demonstrate that the axial-vector interaction plays an important role on the $T-\mu_A$ phase diagram.