How "free" are free neutrons in neutron-star crusts and what does it imply for pulsar glitches ?

TL;DR

This paper investigates the nature of free neutrons in neutron-star crusts, focusing on how entrainment effects influence their coupling with the crust and implications for understanding pulsar glitches.

Contribution

It provides new insights into the entrainment effects on free neutrons in neutron-star crusts and their impact on pulsar glitch models.

Findings

Entrainment significantly affects neutron superfluid dynamics.

Revising pulsar glitch interpretations may be necessary due to entrainment.

Neutron superfluid remains coupled to the crust despite lack of viscous drag.

Abstract

The neutron superfluid permeating the inner crust of mature neutron stars is expected to play a key role in various astrophysical phenomena like pulsar glitches. Despite the absence of viscous drag, the neutron superfluid can still be coupled to the solid crust due to non-dissipative entrainment effects. Entrainment challenges the interpretation of pulsar glitches and suggests that a revision of the interpretation of other observed neutron-star phenomena might be necessary.