Superfluid density in disordered pasta phases in neutron star crusts

TL;DR

This paper calculates the superfluid density in disordered pasta phases within neutron star crusts, accounting for anisotropy and entrainment effects, using an effective medium approach similar to electrical conductivity models.

Contribution

It introduces a method to compute superfluid densities in disordered neutron star crust phases, incorporating entrainment and anisotropic effects.

Findings

Superfluid density tensors are highly anisotropic in ordered pasta phases.

Derived effective superfluid densities for disordered pasta phases.

Method parallels electrical conductivity calculations in terrestrial matter.

Abstract

We calculate the superfluid density of nucleons in disordered pasta phases in the inner crust of neutron stars using an effective medium approach which parallels that previously used for calculating the electrical conductivity of terrestrial matter. We allow for the effect of entrainment, the fact that the current density of one species of nucleon depends on the gradient of the phase not only of the same species but also of the other species. The superfluid density tensors for the perfectly ordered pasta phases are very anisotropic, and we derive expression for the effective superfluid densities of the disordered phases.