Numerical evidence of chiral magnetic effect in lattice gauge theory

TL;DR

This study provides lattice gauge theory evidence that the chiral magnetic effect causes electric current enhancement along magnetic fields, aligning with experimental observations from heavy ion collisions.

Contribution

The paper offers the first qualitative lattice simulation evidence of the chiral magnetic effect in both equilibrium and non-equilibrium gluon configurations.

Findings

Electric current is enhanced along magnetic fields in lattice simulations.

Magnetic field increases local charge fluctuations in the confinement phase.

Effects diminish in the deconfinement phase, possibly due to thermal screening.

Abstract

The chiral magnetic effect is the generation of electric current of quarks along external magnetic field in the background of topologically nontrivial gluon fields. There is a recent evidence that this effect is observed by the STAR Collaboration in heavy ion collisions at RHIC. In our paper we study qualitative signatures of the chiral magnetic effect using quenched lattice simulations. We find indications that the electric current is indeed enhanced in the direction of the magnetic field both in equilibrium configurations of the quantum gluon fields and in a smooth gluon background with nonzero topological charge. In the confinement phase the magnetic field enhances the local fluctuations of both the electric charge and chiral charge densities. In the deconfinement phase the effects of the magnetic field become smaller, possibly due to thermal screening. Using a simple model of a fireball we obtain a good agreement between our data and experimental results of the STAR Collaboration.