Spin-polarized neutron matter at different orders of chiral effective field theory

TL;DR

This study uses chiral effective field theory to analyze spin-polarized neutron matter, examining energy predictions, convergence, and polarization effects, and finds no evidence of a transition to a polarized phase.

Contribution

It provides a systematic analysis of polarized neutron matter at various chiral orders and cutoff scales, including partial polarization and proton fractions, with insights into convergence and phase behavior.

Findings

No evidence for a transition to a polarized phase.

Energy predictions depend on chiral order and cutoff scale.

Polarized neutron matter behaves nearly like a free Fermi gas.

Abstract

Spin-polarized neutron matter is studied using chiral two- and three-body forces. We focus, in particular, on predictions of the energy per particle in ferromagnetic neutron matter at different orders of chiral effective field theory and for different choices of the resolution scale. We discuss the convergence pattern of the predictions and their cutoff dependence. We explore to which extent fully polarized neutron matter behaves (nearly) like a free Fermi gas. We also consider the more general case of partial polarization in neutron matter as well as the presence of a small proton fraction. In other words, in our calculations, we vary both spin and isospin asymmetries. Confirming the findings of other microscopic calculations performed with different approaches, we report no evidence for a transition to a polarized phase of neutron matter5