Toward Thermalization in Heavy Ion Collisions at Strong Coupling

TL;DR

This paper demonstrates that in a strong coupling regime modeled by AdS/CFT, colliding shock waves inevitably produce black holes, indicating rapid thermalization of quark-gluon plasma in heavy ion collisions.

Contribution

It provides a holographic analysis of shock wave collisions in AdS$_5$, establishing the inevitability of black hole formation and rapid thermalization in the dual gauge theory.

Findings

Black hole formation occurs in all sourceless shock wave collisions in AdS$_5$.

Thermalization time is parametrically shorter than shock wave stopping time.

Supports existing analytic estimates for rapid thermalization in strongly coupled plasma.

Abstract

We find the trapped surface for a collision of two sourceless shock waves in AdS$_5$ and conclude that such collisions always lead to a creation of a black hole in the bulk. Due to holographic correspondence, in the boundary gauge theory this result proves that a thermalized medium (quark-gluon plasma) is produced in heavy ion collisions at strong coupling (albeit in ${\cal N} =4$ super-Yang-Mills theory). We present new evidence supporting the analytic estimate for the time of thermalization that exists in the literature and find that thermalization time is parametrically much shorter than the time of shock wave stopping, indicating that our result may be relevant for description of heavy ion collision experiments.