Holography, Hydrodynamization and Heavy-Ion Collisions

TL;DR

This paper reviews recent holographic approaches to understanding hydrodynamization in strongly-time-dependent gauge theories, especially in the context of ultrarelativistic heavy-ion collisions at RHIC and LHC.

Contribution

It provides an overview of recent developments in holography applied to hydrodynamization, emphasizing conceptual insights and open problems in the field.

Findings

Hydrodynamization occurs rapidly in holographic models.

The hydrodynamic gradient expansion has an asymptotic character.

Holographic collisions shed light on extreme conditions in heavy-ion experiments.

Abstract

In the course of the past several years holography has emerged as an ab initio tool in exploring strongly-time-dependent phenomena in gauge theories. These lecture notes overview recent developments in this area driven by phenomenological questions concerning applicability of hydrodynamics (hydrodynamization) under extreme conditions occurring in ultrarelativistic heavy-ion collisions at RHIC and LHC. The topics include hydrodynamization time scale, holographic collisions, as well as hydrodynamization from the point of view of the asymptotic character of the hydrodynamic gradient expansion. The emphasis is put on concepts rather than calculational techniques and a particular attention is devoted to present these developments in the context of the most recent advances and some of the open problems.