Self-consistent energy density functional approaches to the crust of neutron stars

Takashi Nakatsukasa

doi:10.1051/epjconf/202226011041

Abstract

In order to study structure of the crust in neutron stars, we develop a finite-temperature Skyrme-Hartree-Fock method in the full three-dimensional coordinate space using the Fermion operator expansion method. It provides us with a possible order-N approach to non-uniform neutron-star matters.

Highlights

The neutron star is a compact star whose radius is about 10 km, which can be regarded as a giant nucleus with macroscopic numbers of hadrons
The method was successfully applied to non-uniform nuclear matter with superfluid neutrons at finite temperature. We present another coordinate-space solver using the Fermion operator expansion (FOE) method [6]
The conventional approaches to the density functional theory scales as N3, where N is the number of particles

Summary

Introduction

The neutron star is a compact star whose radius is about 10 km, which can be regarded as a giant nucleus with macroscopic numbers of hadrons (baryons and mesons). Since a new exotic structure may appear in certain conditions, the calculation without any symmetry restriction is desired. Structure of these non-uniform exotic nuclear matter have been studied with the ThomasFermi (local density) approximation [1] and/or with the Wigner-Seitz approximation [2]. The method was successfully applied to non-uniform nuclear matter with superfluid neutrons at finite temperature. The conventional approaches to the density functional theory scales as N3, where N is the number of particles. Calculation of the non-uniform neutron star matter may require us to treat more than thousands of nucleons (baryons) in a large space. We demonstrate a test calculation of the FOE method for non-uniform nuclear matter at finite temperature

Fermion operator expansion method

Application of the FOE method