Quantum Monte Carlo calculations of neutron matter with chiral three-body forces

TL;DR

This paper uses quantum Monte Carlo methods with local chiral three-nucleon forces to accurately compute the properties of neutron matter and neutron drops, highlighting regulator dependence effects.

Contribution

It introduces the inclusion of local chiral three-nucleon interactions in QMC simulations, advancing the accuracy of neutron matter calculations.

Findings

Local regulators produce less repulsion from 3N forces compared to nonlocal regulators.

Results include neutron matter equations of state and neutron drop energies and radii.

Study of regulator dependence at Hartree-Fock and AFDMC levels.

Abstract

Chiral effective field theory (EFT) enables a systematic description of low-energy hadronic interactions with controlled theoretical uncertainties. For strongly interacting systems, quantum Monte Carlo (QMC) methods provide some of the most accurate solutions, but they require as input local potentials. We have recently constructed local chiral nucleon-nucleon (NN) interactions up to next-to-next-to-leading order (N$^2$LO). Chiral EFT naturally predicts consistent many-body forces. In this paper, we consider the leading chiral three-nucleon (3N) interactions in local form. These are included in auxiliary field diffusion Monte Carlo (AFDMC) simulations. We present results for the equation of state of neutron matter and for the energies and radii of neutron drops. In particular, we study the regulator dependence at the Hartree-Fock level and in AFDMC and find that present local regulators lead to less repulsion from 3N forces compared to the usual nonlocal regulators.