Long-Range Rapidity Correlations in Heavy Ion Collisions at Strong Coupling from AdS/CFT

TL;DR

This paper uses AdS/CFT to analyze long-range rapidity correlations in heavy ion collisions, revealing early-time correlations that persist despite medium evolution, offering insights into observed experimental 'ridge' phenomena.

Contribution

It introduces a holographic model of heavy ion collisions showing early-time long-range correlations that survive hydrodynamic evolution, linking theory to experimental observations.

Findings

Early-time correlations are long-range in rapidity.

Hydrodynamic evolution does not erase initial correlations.

Results relate to the 'ridge' phenomena in experiments.

Abstract

We use AdS/CFT correspondence to study two-particle correlations in heavy ion collisions at strong coupling. Modeling the colliding heavy ions by shock waves on the gravity side, we observe that at early times after the collision there are long-range rapidity correlations present in the two-point functions for the glueball and the energy-momentum tensor operators. We estimate rapidity correlations at later times by assuming that the evolution of the system is governed by ideal Bjorken hydrodynamics, and find that glueball correlations in this state are suppressed at large rapidity intervals, suggesting that late-time medium dynamics can not "wash out" the long-range rapidity correlations that were formed at early times. These results may provide an insight on the nature of the "ridge" correlations observed in heavy ion collision experiments at RHIC and LHC, and in proton-proton collisions at LHC.