Thermalization and Bose-Einstein Condensation in Overpopulated Glasma

TL;DR

This paper investigates how overpopulated gluonic matter in early heavy ion collisions leads to rapid thermalization and the potential formation of a transient Bose-Einstein Condensate, using a kinetic approach.

Contribution

It introduces a kinetic framework to describe thermalization and Bose-Einstein Condensation in overpopulated Glasma, highlighting emergent properties of weakly coupled but highly occupied gluonic matter.

Findings

Identification of the role of overpopulation in rapid thermalization

Development of a kinetic model for Glasma evolution

Numerical evidence for transient Bose-Einstein Condensate formation

Abstract

We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the far-from-equilibrium gluonic matter ("Glasma") is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an {\em emergent property} of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scattering. A possible transient Bose-Einstein Condensate is argued to form dynamically on a rather general ground. We develop a kinetic approach for describing its evolution toward thermalization, and based on that we find approximate scaling solutions as well as numerically study the onset of condensation.