Equation of state of superfluid neutron matter and the calculation of $^1S_0$ pairing gap

TL;DR

This paper uses Quantum Monte Carlo methods to accurately determine the equation of state and $^1S_0$ pairing gap of low-density neutron matter, revealing a weaker suppression of the gap than previous models.

Contribution

It provides a precise Quantum Monte Carlo calculation of neutron matter properties including the pairing gap with realistic nuclear interactions.

Findings

Weak suppression of the pairing gap compared to BCS theory

Accurate equation of state for low-density neutron matter

Validation of nuclear Hamiltonian models in neutron matter calculations

Abstract

We present a Quantum Monte Carlo study of the zero temperature equation of state of neutron matter and the computation of the $^1S_0$ pairing gap in the low-density regime with $\rho<0.04$ fm$^{-3}$. The system is described by a non-relativistic nuclear Hamiltonian including both two-- and three--nucleon interactions of the Argonne and Urbana type. This model interaction provides very accurate results in the calculation of the binding energy of light nuclei. A suppression of the gap with respect to the pure BCS theory is found, but sensibly weaker than in other works that attempt to include polarization effects in an approximate way.