Bjorken Flow of the quark-gluon plasma and Gauge/Gravity Correspondence

TL;DR

This paper reviews the Gauge/Gravity duality approach to modeling the hydrodynamic expansion of the quark-gluon plasma in heavy-ion collisions, highlighting recent advances in understanding far-from-equilibrium dynamics and thermalization at strong coupling.

Contribution

It introduces new results on early-time expansion and insights into the far-from-equilibrium behavior of the plasma using gauge/gravity duality in a boost-invariant setting.

Findings

New understanding of far-from-equilibrium plasma dynamics

Insights into thermalization and isotropization processes

Early-time expansion results in strong coupling regime

Abstract

The contribution presents a brief summary of the Gauge/Gravity approach to the study of hydrodynamic flow of the quark-gluon plasma formed in heavy-ion collisions, in a boost-invariant setting (Bjorken flow). Considering the ideal case of a supersymmetric Yang-Mills theory for which the AdS/CFT correspondence gives a precise form of the Gauge/Gravity duality, the properties of the strongly coupled expanding plasma are put in one-to-one correspondence with the metric of a 5-dimensional black hole with the horizon moving away in the 5th dimension and its deformations consistent with the relevant Einstein equations. Several recently studied aspects of this framework are recalled and put in perspective. New results in collaboration with G.Beuf and M.Heller on the early time expansion towards the hydrodynamical regime are provided giving a new insight on the far-from-equilibrium behavior of the fluid at strong coupling and the thermalization and isotropization problems.