Superfluidity in Disordered Neutron Stars Crusts

Abstract

Nonequilibrium conditions imposed by neutrino cooling through the liquid-solid transition lead to disorder in the solid crust of neutron stars. Disorder reduces the superfluid fraction, $\ddot{I}{}_s/\ddot{I}$, at densities above that of neutron drip, $\ddot{I}{}_d\approx 4\times 10^{11}g/c{m}^3$. For an amorphous solid crust the suppression of $\ddot{I}{}_s$ is small, except in the highest density regions of the crust. In contrast to the strong reduction in neutron conduction predicted for coherent Bragg scattering in a crystalline crust, the disordered solid crust supports sufficient neutron superfluid density to account for pulsar glitches.

6 pages, 5 figures