Gravitational susceptibility of QGP

TL;DR

This paper investigates the gravitational susceptibility of strongly coupled nonconformal quark-gluon plasma using holographic models, highlighting its scheme dependence and proposing a temperature derivative as a universal characteristic.

Contribution

It introduces the temperature derivative of gravitational susceptibility as a scheme-independent measure and analyzes its critical behavior near phase transitions.

Findings

Gravitational susceptibility is scheme-dependent in theories with relevant couplings.

The temperature derivative of susceptibility is proposed as a universal, scheme-independent characteristic.

Critical behavior of susceptibility varies near thermal phase transitions.

Abstract

We use ${\cal N}=2^*$ and cascading gauge theory holographic models to extract the general features of the gravitational susceptibility $\kappa$ of strongly coupled nonconformal quark-gluon plasma. We show that in theories with a relevant coupling constant the gravitational susceptibility is renormalization scheme dependent. We propose to use its temperature derivative, i.e., $\frac{d\kappa}{d\ln T}$, as a scheme-independent characteristic of a QGP. Although $\kappa$ is a thermodynamic quantity, its critical behavior can be drastically distinct in the vicinity of seemingly identical thermal phase transitions.