Fragile Black Holes and an Angular Momentum Cutoff in Peripheral Heavy Ion Collisions

TL;DR

This paper models the angular momentum in heavy ion collisions using AdS/CFT duality, revealing a potential instability in the quark-gluon plasma at high angular momenta and suggesting a practical cutoff for observable effects.

Contribution

It introduces a geometric model linking rotating AdS black holes to QGP in heavy ion collisions and uncovers an instability related to angular momentum in the holographic dual.

Findings

Black hole instability occurs at high angular momentum.

Holography predicts a cutoff in observable angular momenta.

Instability may only manifest in collisions with large impact parameters.

Abstract

In collisions of heavy ions at extremely high energies, it is possible for a significant quantity of angular momentum to be deposited into the Quark-Gluon Plasma which is thought to be produced. We develop a simple geometric model of such a system, and show that it is dual, in the AdS/CFT sense, to a rotating AdS black hole with a topologically planar event horizon. However, when this black hole is embedded in string theory, it proves to be unstable, for all non-zero angular momenta, to a certain non-perturbative effect: the familiar planar black hole, as used in most AdS/CFT analyses of QGP physics, is "fragile". The upshot is that the AdS/CFT duality apparently predicts that the QGP should always become unstable when it is produced in peripheral collisions. However, we argue that holography indicates that relatively low angular momenta delay the development of the instability, so that in practice it may be observable only for peripheral collisions involving favourable impact parameters, generating extremely large angular momenta. The result may be holographic prediction of a cutoff for the observable angular momenta of the QGP, or perhaps of an analogous phenomenon in condensed matter physics.