Pairing in pure neutron matter

TL;DR

This paper reviews superfluid pairing in pure neutron matter, covering s-wave and p-wave pairing, comparing theoretical approaches, and discussing uncertainties at different densities.

Contribution

It provides a comprehensive comparison of many-body approaches and quantum Monte Carlo results for neutron matter pairing, highlighting current challenges.

Findings

Agreement between approaches at low densities for s-wave pairing

Uncertainties in p-wave pairing due to poorly constrained interactions

Identification of key factors affecting pairing at various densities

Abstract

We review the long standing problem of superfluid pairing in pure neutron matter. For the $s$-wave pairing, we summarize the state of the art of many-body approaches including different $nn$ interactions, medium polarization, short-range correlations and BCS-BEC crossover effects, and compare them with quantum Monte Carlo results at low-densities. We also address pairing in the $p$-wave, which appears at higher densities and hence has large uncertainties due to the poorly constrained interactions, medium effects and many-body forces.