Maximally local two-nucleon interactions at N$^3$LO in $\Delta$-less chiral effective field theory

TL;DR

This paper introduces new maximally local two-nucleon interactions derived in delta-less chiral effective field theory up to N$^3$LO, fit to phase shifts, suitable for quantum Monte Carlo methods, and relevant for nuclear and astrophysical studies.

Contribution

The paper develops and fits new local two-nucleon interactions at N$^3$LO in delta-less chiral EFT, enabling improved nuclear structure calculations.

Findings

Interactions fit to phase shifts across cutoff range

Suitable for quantum Monte Carlo methods

Provides benchmarks for nuclear and astrophysical phenomena

Abstract

We present new maximally local two-nucleon interactions derived in $\Delta$-less chiral effective field theory up to next-to-next-to-next-to-leading order (N$^3$LO), which include all contact and pion-exchange contributions to the nuclear Hamiltonian up to this order. Our interactions are fit to nucleon-nucleon phase shifts using a Bayesian statistical approach, and explore a wide cutoff range from $0.6-0.9$ fm ($\approx 660 - 440$ MeV). These interactions can be straightforwardly employed in quantum Monte Carlo methods, such as the auxiliary field diffusion Monte Carlo method. Together with local three-nucleon forces, calculations with these new interactions will provide improved benchmarks for the structure of atomic nuclei and serve as crucial input to analyses of astrophysical phenomena of neutron stars, such as binary neutron-star mergers.