# Viscosity vs. Vorticity in the Quark-Gluon Plasma

## TL;DR

This paper uses holographic models to explore how vorticity in the Quark-Gluon Plasma affects its viscosity and entropy density, revealing that peripheral collisions exhibit significantly different properties from central ones.

## Contribution

It demonstrates, through a holographic approach, that vorticity can suppress entropy density and reduce shear viscosity in peripheral Quark-Gluon Plasma, highlighting new effects of vorticity on QGP properties.

## Key findings

- Peripheral plasmas have lower entropy density than central plasmas.
- Vorticity strongly influences the shear viscosity of the plasma.
- Implications for jet quenching and other QGP phenomena.

## Abstract

We show that, in a holographic or gauge-gravity approach to the study of the Quark-Gluon Plasma, the specific entropy density of the plasma produced in a peripheral heavy-ion collision can be strongly suppressed relative to its value for central collisions at the same impact energy; this is connected with the strong vorticity fields which are now known to characterize the peripheral case. This implies, within the holographic model, that the shear viscosity of `peripheral plasmas' may be considerably lower than that of the corresponding `central plasmas', with potentially important consequences for other aspects of QGP physics, such as the centrality dependence of jet quenching.