Dynamical evolution of magnetic field in the pre-equilibrium quark-gluon plasma

TL;DR

This paper develops a kinetic model to study how magnetic fields decay in the early, pre-equilibrium stage of quark-gluon plasma created in high-energy heavy-ion collisions, providing insights into magnetic field longevity.

Contribution

It introduces the first kinetic framework coupling Boltzmann and Maxwell equations to analyze magnetic field decay in early QGP stages.

Findings

Magnetic field decay follows a kinetic evolution before hydrodynamics dominates.

A magnetohydrodynamical description emerges at late times.

Estimated residual magnetic field strength at the start of hydrodynamics for RHIC and LHC.

Abstract

High-energy heavy-ion collisions generate extremely strong magnetic field which plays a key role in a number of novel quantum phenomena in quark-gluon plasma (QGP), such as the chiral magnetic effect (CME). However, due to the complexity in theoretical modellings of the coupled electromagnetic fields and the QGP system, especially in the pre-equilibrium stages, the lifetime of the magnetic field in the QGP medium remains undetermined. We establish, for the first time, a kinetic framework to study the dynamical decay of the magnetic field in the early stages of a weakly coupled QGP by solving the coupled Boltzmann and Maxwell equations. We find that at late times a magnetohydrodynamical description of the coupled system emerges. With respect to realistic collisions at RHIC and the LHC, we estimate the residual strength of the magnetic field in the QGP when the system start to evolve hydrodynamically.