Chiral dynamics in QCD at finite chemical potential

TL;DR

This paper develops a renormalized Taylor expansion approach to study the chiral condensate's behavior at finite chemical potential in QCD, revealing insights into pion fluctuations and the phase diagram.

Contribution

It introduces a method to analyze the chiral condensate at finite chemical potential using Taylor expansion and Ward identities, providing continuum limit results in quenched and two-flavor QCD.

Findings

Quadratic response coefficients suggest pion fluctuations decrease near the critical end point.

The approach links meson susceptibilities with the quark mass dependence of quark number susceptibilities.

Results can test features of the QCD phase diagram.

Abstract

We present the renormalized Taylor expansion of the chiral condensate with chemical potential. The relation with the Taylor coefficients of meson susceptibilities and the quark mass dependence of the quark number susceptibilities are obtained through chiral Ward identities and Maxwell relations. The continuum limit is obtained in quenched and two flavour QCD. In Nf=2 QCD, the quadratic response coefficients (QRCs) of the chiral condensate to chemical potential indicate that pion fluctuations decrease at finite chemical potential toward the critical end point. We discuss how these observables can be used to test other features of the QCD phase diagram.