# Superfluid Density of Neutrons in the Inner Crust of Neutron Stars: New Life for Pulsar Glitch Models

## TL;DR

This paper revises previous estimates of neutron superfluid density in neutron star crusts, showing that band structure effects are less suppressive than once thought, which supports crust-based glitch models.

## Contribution

It introduces a mean-field approach inspired by ultracold atomic gases to reassess the impact of band structure on neutron superfluid density in neutron star crusts.

## Key findings

- Band structure effects are less suppressive when pairing gaps are large.
- Revised superfluid density estimates support crust-based glitch models.
- Previous models underestimated the neutron superfluid density.

## Abstract

Calculations of the effects of band structure on the neutron superfluid density in the crust of neutron stars made under the assumption that the effects of pairing are small [N. Chamel, Phys. Rev. C 85, 035801 (2012)] lead to moments of inertia of superfluid neutrons so small that the crust alone is insufficient to account for the magnitude of neutron star glitches. Inspired by earlier work on ultracold atomic gases in an optical lattice, we investigate fermions with attractive interactions in a periodic lattice in the mean-field approximation. The effects of band structure are suppressed when the pairing gap is of order or greater than the strength of the lattice potential. By applying the results to the inner crust of neutron stars, we conclude that the reduction of the neutron superfluid density is considerably less than previously estimated and, consequently, it is premature to rule out models of glitches based on neutron superfluidity in the crust.