Quantum Monte Carlo study of inhomogeneous neutron matter

TL;DR

This paper uses Quantum Monte Carlo methods to study inhomogeneous neutron matter, providing ab-initio results that suggest improvements to Skyrme forces for modeling neutron-rich systems.

Contribution

It offers the first ab-initio calculations of neutron drops with Quantum Monte Carlo, comparing results with Skyrme forces and proposing modifications for better accuracy.

Findings

Re-adjustment of the Skyrme gradient term is necessary.

Ab-initio energies and densities differ from Skyrme predictions.

Guidelines for improving Skyrme forces for neutron-rich nuclei.

Abstract

We present an ab-initio study of neutron drops. We use Quantum Monte Carlo techniques to calculate the energy up to 54 neutrons in different external potentials, and we compare the results with Skyrme forces. We also calculate the rms radii and radial densities, and we find that a re-adjustment of the gradient term in Skyrme is needed in order to reproduce the properties of these systems given by the ab-initio calculation. By using the ab-initio results for neutron drops for close- and open-shell configurations, we suggest how to improve Skyrme forces when dealing with systems with large isospin-asymmetries like neutron-rich nuclei.