From finite nuclei to neutron stars : the essential role of high-order density dependence in effective forces

TL;DR

This paper introduces an extended effective nuclear interaction model with high-order density dependence, successfully describing both finite nuclei and neutron star properties, including recent gravitational wave observations.

Contribution

It develops a new effective force with high-order density dependence that unifies descriptions of finite nuclei and neutron star matter, improving upon existing models.

Findings

Extended SLy4 force accurately models finite nuclei.

The model reproduces neutron star mass-radius relations.

It aligns with GW170817 gravitational wave data.

Abstract

A unified description of finite nuclei and equation of state of neutron stars present a major challenge as well as opportunities for understandings of nuclear interactions.Inspired by the Lee-Huang-Yang formula of hard-sphere gases, we developed effective nuclear interactions with an additional high-order density dependent term.The original Skyrme force SLy4 is widely used in studies of neutron stars but is not satisfied for global descriptions of finite nuclei. The refitted SLy4${'}$ force can improve descriptions of finite nuclei but slightly reduces the radius of neutron star of 1.4 solar mass.We found that the extended SLy4 force with a higher-order density dependence can properly describe properties of both finite nuclei and GW170817 binary neutron stars, including the mass-radius relation and the tidal deformability. This demonstrated the essential role of high-order density dependence at ultrahigh densities. Our work provides a unified and predictive model for neutron stars, as well as new insights for the future development of effective interactions.