Finite particle-number description of symmetric nuclear matter with spin excitations of high-momentum pairs induced by tensor force

TL;DR

This paper investigates symmetric nuclear matter using a finite particle-number approach, focusing on high-momentum pair excitations induced by tensor forces and their impact on the energy and equation of state.

Contribution

It introduces a finite particle-number method incorporating spin excitations and tensor correlations, providing new insights into nuclear matter properties with realistic interactions.

Findings

High-momentum pair excitations significantly increase kinetic energy.

Tensor correlations influence the density dependence of the total energy.

Results agree with other many-body theories for the equation of state.

Abstract

We study the symmetric nuclear matter using bare nucleon-nucleon ($NN$) interactions with finite particle-number approach within finite cubic boxes. Due to the $NN$ correlations originating from bare $NN$ interaction, two nucleons can be excited to the high-momentum region, leading to the increase of the kinetic energy in nuclear matter. We further consider the spin excitations in the nucleon pairs, where the spin of the two nucleons are changed, and this excitation is important for the tensor correlation. The unitary correlation operator method (UCOM) is used to treat the short-range correlation. The tail correction coming from the neighbouring boxes is also included. We demonstrate the contributions of various excitations of nucleon pairs as well as the tail correction to the total energy at the normal density. We also discuss the effects of UCOM and correlated nucleon pairs on the density dependence of the total energy. We calculate the equations of state of symmetric nuclear matter using two kinds of the Argonne potentials and the results agree with those from other many-body theories. The density dependences of the Hamiltonian components are also shown.