Neutron matter from chiral effective field theory interactions

TL;DR

This paper presents a comprehensive N3LO chiral EFT calculation of neutron matter energy, including many-body forces and uncertainties, with implications for astrophysics and nuclear structure.

Contribution

It provides the first complete N3LO neutron matter energy calculation with subleading three-nucleon and leading four-nucleon forces, advancing theoretical precision.

Findings

Results inform supernova equation of state and neutron star structure.

Estimated many-body contributions are significant for nuclear structure calculations.

Theoretical uncertainties are quantified for neutron matter energy at N3LO.

Abstract

The neutron-matter equation of state constrains the properties of many physical systems over a wide density range and can be studied systematically using chiral effective field theory (EFT). In chiral EFT, all many-body forces among neutrons are predicted to next-to-next-to-next-to-leading order (N3LO). We present details and additional results of the first complete N3LO calculation of the neutron-matter energy, which includes the subleading three-nucleon as well as the leading four-nucleon forces, and provides theoretical uncertainties. In addition, we discuss the impact of our results for astrophysics: for the supernova equation of state, the symmetry energy and its density derivative, and for the structure of neutron stars. Finally, we give a first estimate for the size of the N3LO many-body contributions to the energy of symmetric nuclear matter, which shows that their inclusion will be important in nuclear structure calculations.