Gauge-invariant condensation in the nonequilibrium quark-gluon plasma

TL;DR

This paper introduces a gauge-invariant order parameter for gluon condensation in nonequilibrium quark-gluon plasma, demonstrating through lattice simulations the formation of a zero mode with similarities to ultracold Bose gas phenomena.

Contribution

It proposes a novel gauge-invariant measure for gluon condensation and uses real-time lattice simulations to show the emergence of a zero mode in the plasma.

Findings

Identification of a gauge-invariant order parameter based on Wilson loops.

Demonstration of a self-similar transport process towards low momenta.

Observation of a macroscopic zero mode formation.

Abstract

The large density of gluons, which is present shortly after a nuclear collision at very high energies, can lead to the formation of a condensate. We identify a gauge-invariant order parameter for condensation based on elementary non-perturbative excitations of the plasma, which are described by spatial Wilson loops. Using real-time lattice simulations, we demonstrate that a self-similar transport process towards low momenta builds up a macroscopic zero mode. Our findings reveal intriguing similarities to recent discoveries of condensation phenomena out of equilibrium in table-top experiments with ultracold Bose gases.