Variational and parquet-diagram calculations for neutron matter. IV. Spin-orbit interactions and linear response

TL;DR

This paper develops a parquet-diagram summation method for neutron matter with complex interactions, including spin-orbit effects, and analyzes how many-body correlations screen these interactions, impacting the matter's response to external fields.

Contribution

The paper introduces an exact expression for ring-diagrams with spin, tensor, and spin-orbit interactions and derives the spin-orbit contribution to particle-hole interactions, advancing many-body calculation techniques.

Findings

Many-body correlations significantly screen the bare spin-orbit potential.

Screened spin-orbit corrections to other channels are small.

The method accurately predicts neutron matter response to external fields.

Abstract

We develop the parquet-diagram summation method for neutron matter interacting via potentials that include spin, tensor, and spin-orbit components. For that purpose, we derive an exact expression for the sum of all ring-diagrams in terms effective local particle-hole interactions involving the above four operators. The parquet equations are closed by deriving the spin-orbit contribution to that particle-hole interaction. We show that many-body correlations screen the bare spin-orbit potential considerably, and the corrections of that screened spin-orbit potential to the other three interaction channels are quite small. We apply our method to the calculation of the response of neutron matter to density and both longitudinal and transverse spin-dependent external fields.