Unstable dynamics of Yang-Mills fields at early times of heavy ion collisions

TL;DR

This paper investigates the early-time unstable dynamics of Yang-Mills fields in heavy ion collisions, highlighting how anisotropies and expansion influence plasma instabilities and field growth.

Contribution

It provides a simulation-based analysis of non-abelian plasma instabilities considering early anisotropies and expansion effects in heavy ion collisions.

Findings

Expansion slows down unstable mode growth

Soft gluonic field formation depends on initial conditions

Turbulent cascade observed in strong-field regime

Abstract

The quark gluon plasma as produced in heavy ion collisions is exposed to early anisotropies in momentum space due to its rapid expansion. Such anisotropies can lead to non-abelian plasma instabilities, driven by unstable gluonic modes that can grow exponentially fast. These plasma instabilities can be simulated using a discretized version of gauge-covariant Boltzmann-Vlasov and Yang-Mills equations. In the stationary case, a turbulent cascade forms in the strong-field regime, which is associated with an approximately linear growth of energy in collective fields. Early longitudinal expansion slows down the growth of unstable modes, and the formation of soft gluonic fields depends crucially on the initial conditions assumed.