The chiral condensate in neutron matter

TL;DR

This paper calculates the behavior of the chiral condensate in neutron matter using chiral effective field theory, showing that interactions hinder chiral symmetry restoration at densities near nuclear saturation.

Contribution

It provides a comprehensive calculation of the chiral condensate in neutron matter including multi-nucleon interactions up to N3LO, indicating the unlikelihood of a chiral phase transition at typical nuclear densities.

Findings

Interaction effects modestly increase the condensate

Chiral symmetry restoration is unlikely near saturation density

Dense neutron matter does not favor a chiral phase transition

Abstract

We calculate the chiral condensate in neutron matter at zero temperature based on nuclear forces derived within chiral effective field theory. Two-, three- and four-nucleon interactions are included consistently to next-to-next-to-next-to-leading order (N3LO) of the chiral expansion. We find that the interaction contributions lead to a modest increase of the condensate, thus impeding the restoration of chiral symmetry in dense matter and making a chiral phase transition in neutron-rich matter unlikely for densities that are not significantly higher than nuclear saturation density.