Thermodynamics of the in-medium chiral condensate

TL;DR

This paper studies how the chiral condensate behaves with temperature and density in nuclear matter using a systematic chiral effective field theory approach, finding chiral symmetry remains broken up to certain conditions.

Contribution

It provides a detailed, systematic calculation of the in-medium chiral condensate's temperature dependence using advanced many-body chiral effective field theory methods.

Findings

Chiral symmetry remains broken up to T ≈ 100 MeV and twice nuclear saturation density.

Nuclear matter stays in the Nambu-Goldstone phase under studied conditions.

Systematic inclusion of multi-loop processes enhances the understanding of in-medium chiral dynamics.

Abstract

The temperature dependence of the chiral condensate in isospin-symmetric nuclear matter at varying baryon densities is investigated starting from a realistic free energy density of the correlated nuclear many-body system. The framework is thermal in-medium chiral effective field theory which permits a systematic calculation of the quark mass dependence of the free energy density. One- and two-pion exchange processes, virtual $\Delta(1232)$-isobar excitations and Pauli blocking corrections are treated up to and including three-loop order. It is found that nuclear matter remains in the Nambu-Goldstone phase with spontaneously broken chiral symmetry at least in the range of temperatures $T\lesssim 100\,$MeV and baryon densities up to about twice the density of normal nuclear matter.