Rotating self-gravitating Bose-Einstein condensates with a crust: a minimal model for pulsar glitches

TL;DR

This paper models pulsar glitches using a rotating Bose-Einstein condensate with a crust potential, revealing vortex dynamics and self-organized criticality consistent with observations.

Contribution

It introduces a minimal 3D Gross-Pitaevskii-Poisson model with a crust potential to simulate pulsar glitches and vortex interactions.

Findings

Vortices are generated in rotating bosonic stars without crust.

Vortex-crust interactions produce stick-slip behavior and glitches.

Event size, duration, and waiting time distributions show SOC signatures.

Abstract

We develop a minimal model for \textit{pulsar glitches} by introducing a solid-crust potential in the three-dimensional (3D) Gross-Pitaevskii-Poisson equation (GPPE), which we have used earlier to study gravitationally bound Bose-Einstein Condensates (BECs), i.e., bosonic stars. In the absence of the crust potential, we show that, if we rotate such a bosonic star, it is threaded by vortices. We then show, via extensive direct numerical simulations (DNSs), that the interaction of these vortices with the crust potential yields (a) stick-slip dynamics and (b) dynamical glitches. We demonstrate that, if enough momentum is transferred to the crust from the bosonic star, then the vortices are expelled from the star and the crust's angular momentum $J_c$ exhibits features that can be interpreted naturally as glitches. From the time series of $J_c$, we compute the cumulative probability distribution functions (CPDFs) of event sizes, event durations, and waiting times. We show that these CPDFs have signatures of self-organized criticality (SOC), which have been seen in observations on pulsar glitches.