Is there Nuclear Pinning of Vortices in Superfluid Pulsars?

We develop a fully consistent semianalytical model in order to study the vortex-nucleus interaction in the inner crust of neutron stars. In the framework of the local-density approximation and assuming a constant pairing gap and a square-well nuclear potential, the model takes into account all energy contributions and determines unambiguously the structure of the vortex core. The results show that, irrespective of the value of the pairing gap, only interstitial pinning takes place all along the inner crust. This is in contrast with all existing calculations, which predict nuclear pinning in the deeper layers of the crust. Should further studies confirm this surprising result, the explanation of pulsar glitches in terms of depinning of vortices will have to be carefully revisited.