Analysis of the neutron matter equation of state and the symmetry energy up to fourth order of chiral effective field theory

Abstract

We present predictions for the neutron matter equation of state, from leading to fourth order of chiral effective field theory, using recently developed, accurate chiral nucleon-nucleon potentials. We find the impact of subleading three-neutron forces to be mild and attractive. We also show order-by-order predictions for the symmetry energy, and discuss its density dependence in relation to empirical constraints.

An overview of symmetric nuclear matter properties from chiral interactions up to fourth order of the chiral expansion

“…Having the EoS for SNM and NM [62] consistently at N 3 LO, we are in the position to revisit neutron skins and neutron stars. Our work in progress includes another form of correlations, namely pairing in nuclear and neutron matter.…”

“…In a recent work [62], we concentrated on the neutron matter (NM) EoS and the density dependence of the symmetry energy with chiral 2NFs and 3NFs up to N 3 LO, order-by-order and with proper chiral uncertainty quantification. Our main focal point was the symmetry energy, which we discussed in relation to recent empirical constraints [63].…”

Unbiased interpolated neutron-star EoS at finite T for modified gravity studies

“…Fig.1. Equation of State of pure neutron matter for low density, taken from the ChPT computations of the nuclear potential[24,25,26], with T increasing from bottom to top in 10 MeV steps. As the number density rises, the uncertainty grows and the bands do overlap, so that the effect of temperatures much smaller than the densities is less visible.…”