Thermalization of the quark-gluon plasma and dynamical formation of Bose-Einstein Condensate

TL;DR

This paper explores the thermalization process of the quark-gluon plasma in heavy ion collisions, emphasizing the role of overpopulated gluonic matter and the potential formation of a transient Bose-Einstein Condensate, using kinetic theory methods.

Contribution

It introduces a kinetic approach to describe overpopulated gluonic systems and demonstrates the possible dynamical formation of a Bose-Einstein Condensate during thermalization.

Findings

Emergent strong interactions from weakly coupled, highly occupied gluon states.

Approximate scaling solutions for the kinetic evolution.

Numerical evidence for the onset of Bose-Einstein Condensation.

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 pre-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 the kinetic approach for describing this highly overpopulated system and find approximate scaling solutions as well as numerically study the onset of condensation. Finally we discuss possible phenomenological implications.