Quark Number Susceptibility with Finite Chemical Potential in Holographic QCD

TL;DR

This paper investigates quark number susceptibility in holographic QCD at finite chemical potential and magnetic field, revealing critical behavior near phase transitions and confirming lattice QCD results.

Contribution

It introduces a holographic QCD model analyzing quark number susceptibility under chemical potential and magnetic field, highlighting critical phenomena and phase transition signatures.

Findings

Susceptibility peaks near critical temperature at high chemical potential

Susceptibility diverges at low temperature with increasing magnetic field

Results align with lattice QCD observations

Abstract

We study the quark number susceptibility in holographic QCD with a finite chemical potential or under an external magnetic field at finite temperature. We first consider the quark number susceptibility with the chemical potential. We observe that approaching the critical temperature from high temperature regime, the quark number susceptibility divided by temperature square develops a peak as we increase the chemical potential, which confirms recent lattice QCD results. We discuss this behavior in connection with the existence of the critical end point in the QCD phase diagram. We also consider the quark number susceptibility under the external magnetic field. We predict that the quark number susceptibility exhibits a blow-up behavior at low temperature as we raise the value of the magnetic field. We finally spell out some limitations of our study.