Exact-exchange density functional theory for neutron drops

TL;DR

This paper applies an exact-exchange density functional theory to neutron drops, showing it closely matches Hartree-Fock results and advancing ab initio nuclear functional development.

Contribution

It demonstrates that an orbital-dependent functional can achieve Hartree-Fock accuracy for neutron drops, paving the way for more realistic nuclear density functionals.

Findings

Exact-exchange DFT closely matches Hartree-Fock results.

Orbital-dependent functional improves nuclear DFT accuracy.

First step towards ab initio nuclear functionals based on realistic interactions.

Abstract

We compute the ground-state properties of finite systems of neutrons in an external harmonic trap, interacting via the Minnesota potential, using the "exact-exchange" form of orbital-dependent density functional theory. We compare our results with Hartree-Fock calculations and find very close agreement. Within the context of the interaction studied, we conclude that this simple orbital-dependent functional brings conventional nuclear density functional theory to the level of Hartree-Fock in an ab initio fashion. Our work is a first step towards higher-order ab initio nuclear functionals based on realistic nucleon-nucleon interactions.