Finite-size effects and collective vibrations in the inner crust of neutron stars

TL;DR

This paper investigates the collective vibrational modes and finite-size effects in the inner crust of neutron stars using the Random Phase Approximation with Skyrme interactions, focusing on the nucleus-neutron sea interactions within a Wigner-Seitz cell.

Contribution

It provides a detailed analysis of surface vibrations and their coupling with free neutron modes, incorporating shell effects and resonant states in the inner crust modeling.

Findings

Identification of surface vibration modes and their interaction with neutron sea

Role of shell effects and resonant states in vibrational properties

Insights into finite-size effects on neutron star crust dynamics

Abstract

We study the linear response of the inner crust of neutron stars within the Random Phase Approximation, employing a Skyrme-type interaction as effective interaction. We adopt the Wigner-Seitz approximation, and consider a single unit cell of the Coulomb lattice which constitutes the inner crust, with a nucleus at its center, surrounded by a sea of free neutrons. With the use of an appropriate operator, it is possible to analyze in detail the properties of the vibrations of the surface of the nucleus and their interaction with the modes of the sea of free neutrons, and to investigate the role of shell effects and of resonant states.