Shearing Black Holes and Scans of the Quark Matter Phase Diagram

TL;DR

This paper models how shearing motions in quark-gluon plasmas, produced in heavy ion collisions, can lead to instabilities that vary across the quark matter phase diagram, impacting observable effects.

Contribution

It introduces a holographic model linking shear-induced instabilities in quark-gluon plasma to the phase diagram, revealing faster transitions at higher chemical potentials.

Findings

Instability onset accelerates at higher chemical potentials.

Shearing motions can induce turbulence in quark-gluon plasma.

Implications for the observability of quark polarization effects.

Abstract

Future facilities such as FAIR and NICA are expected to produce collisions of heavy ions generating quark-gluon plasmas with large values of the quark chemical potential; peripheral collisions in such experiments will also lead to large values of the angular momentum density, associated with the internal shearing motion of the plasma. It is well known that shearing motions in fluids can lead to instabilities which cause a transition from laminar to turbulent flow, and such instabilities in the QGP have recently attracted some attention. We set up a holographic model of this situation by constructing a gravitational dual system exhibiting an instability which is indeed triggered by shearing angular momentum in the bulk. We show that holography indicates that the transition to an unstable fluid happens more quickly as one scans across the quark matter phase diagram towards large values of the chemical potential. This may have negative consequences for the observability of quark polarization effects.