Structure Factors for Hot Neutron Matter from Ab Initio Lattice Simulations

We present the first ab initio lattice calculations of spin and density correlations in hot neutron matter using
high-fidelity interactions at next-to-next-to-next-to-leading order (N3LO) in chiral effective field theory. These
correlations have a large impact on neutrino heating and shock revival in core-collapse supernovae and are
encapsulated in functions called structure factors. Unfortunately, calculations of structure factors using highfidelity chiral interactions were well out of reach using existing computational methods. In this work, we solve
the problem using a computational approach called the rank-one operator (RO) method. The RO method is a
general technique with broad applications to simulations of fermionic many-body systems. It uses the fact that
the determinant of a matrix composed of rank-one operators is at most linear in each operator coefficient. Using
the RO method, we compute the vector and axial static structure factors for hot neutron matter as a function of
temperature and density. The ab initio lattice results are in good agreement with virial expansion calculations
at low densities and can be used to calibrate random phase approximation codes commonly used to estimate
many-body effects on the neutrino opacity in core-collapse supernovae