How the Quark Number fluctuates in QCD at small chemical potential

TL;DR

This paper analyzes how quark number fluctuates in QCD at small chemical potential, revealing complex distributions and cancellations using chiral perturbation theory.

Contribution

It provides a novel analysis of quark number distribution in QCD at nonzero chemical potential using leading order chiral perturbation theory.

Findings

Distribution is over the complex plane due to non-hermitian operator

Fermion determinant causes the distribution to be non-real and non-positive

Insights into cancellations affecting total baryon number

Abstract

We discuss the distribution of the quark number over the gauge fields for QCD at nonzero quark chemical potential. As the quark number operator is non-hermitian, the distribution is over the complex plane. Moreover, because of the fermion determinant, the distribution is not real and positive. The computation is carried out within leading order chiral perturbation theory and gives direct insight into the delicate cancellations that take place in contributions to the total baryon number.