Lattice study of electromagnetic conductivity of quark-gluon plasma in external magnetic field

TL;DR

This study uses lattice simulations to analyze how electromagnetic conductivity in quark-gluon plasma varies with magnetic fields, revealing anisotropic behavior and evidence for the Chiral Magnetic Effect and magnetoresistance.

Contribution

It provides the first lattice-based quantitative analysis of electromagnetic conductivity in QGP under magnetic fields at physical quark masses.

Findings

Conductivity increases along magnetic field direction.

Conductivity decreases perpendicular to magnetic field.

Evidence supports the Chiral Magnetic Effect and magnetoresistance in QGP.

Abstract

We study the electromagnetic (e.m.) conductivity of QGP in a magnetic background by lattice simulations with $N_f = 2+1$ dynamical rooted staggered fermions at the physical point. We study the correlation functions of the e.m.~currents at $T=200,\,250$\,MeV and use the Tikhonov approach to extract the conductivity. This is found to rise with the magnetic field in the direction parallel to it and to decrease in the transverse direction, giving evidence for both the Chiral Magnetic Effect and the magnetoresistance phenomenon in QGP. We also estimate the chiral charge relaxation time in QGP.