Hot origin of the Little Bang

TL;DR

This paper demonstrates that in ultrarelativistic heavy ion collisions, the Minkowski vacuum appears as a thermal state in the Little Bang region, providing insights into early thermalization mechanisms similar to the Unruh effect.

Contribution

It reveals a novel analogy between the vacuum state in heavy ion collisions and the Unruh effect, offering a new perspective on early thermalization.

Findings

Minkowski vacuum appears as a thermal state in the Little Bang region.

The analogy with the Unruh effect explains early time thermalization.

Provides a theoretical framework for understanding initial thermalization in heavy ion collisions.

Abstract

Ultrarelativistic heavy ion collisions produce a quark-gluon matter which lies in the future light cone originating from given points on the $t=z=0$ plane of the Minkowski spacetime manifold. We show that in a weak coupling regime the Minkowski vacuum of massless fields presents itself in the "Little Bang" region as a thermal state of low $p_{T}$ particles, in close analogy to the Unruh effect for uniformly accelerated observers which are causally restricted to a Rindler wedge. It can shed some light on the mechanisms of early time thermalization in ultrarelativistic heavy ion collisions.