Spin-polarized low-density neutron matter

TL;DR

This paper presents the first ab initio Quantum Monte Carlo simulations of spin-polarized low-density neutron matter, revealing linear energy dependence on polarization and providing insights relevant to neutron stars and nuclear physics.

Contribution

It introduces novel ab initio Quantum Monte Carlo results for polarized neutron matter, extending understanding to imbalanced populations in low-density regimes.

Findings

Energy depends linearly on polarization for small imbalances

Proportionality coefficient varies with density

Provides momentum and pair distribution data

Abstract

Low-density neutron matter is relevant to the study of neutron-rich nuclei and neutron star crusts. Unpolarized neutron matter has been studied extensively over a number of decades, while experimental guidance has recently started to emerge from the field of ultracold atomic gases. In this work, we study population-imbalanced neutron matter (possibly relevant to magnetars and to density functionals of nuclei) applying a Quantum Monte Carlo method that has proven successful in the field of cold atoms. We report on the first ab initio simulations of superfluid low-density polarized neutron matter. For systems with small imbalances, we find a linear dependence of the energy on the polarization, the proportionality coefficient being dependent on the density. We also present results for the momentum and pair distributions of the two fermionic components.