Exploring Interplays Between $^3\text{P}_2$ Neutron Superfluid Vortices and $^1\text{S}_0$ Proton Fluxtubes in the Outer Core of Neutron Stars

TL;DR

This paper develops a microscopic model to study the interaction between neutron superfluid vortices and proton fluxtubes in neutron star cores, aiming to better understand their role in pulsar glitches.

Contribution

It introduces a combined spin-2 Gross-Pitaevskii and Ginzburg-Landau framework to explore vortex-fluxtube interactions in neutron star outer cores.

Findings

Vortex shapes are affected by nearby proton fluxtubes.

The model provides insights into vortex-fluxtube coupling mechanisms.

Preliminary results suggest potential impacts on pulsar glitch explanations.

Abstract

In the outer core of neutron stars, $^3$P$_2$ superfluid neutrons and $^1$S$_0$ superconducting protons are deemed to exist, forming quantum vortices and magnetic fluxtubes, respectively. Those quantum vortices and fluxtubes play an important role in explaining observed sudden changes of rotational frequency, known as pulsar ``glitches.'' While the most of conventional glitch models rely on pinning/unpinning dynamics of neutron $^1\text{S}_0$ superfluid vortices in the inner crust, contributions of the outer core have not been ruled out. However, the latter possibility has been less explored so far and further thorough investigations are desired. In this study, we are thus developing a microscopic model based on spin-2 Gross-Pitaevskii equation (GPE) for neutron $^3$P$_2$ superfluid vortices coupled with Ginzburg-Landau equation (GLE) for fluxtubes associated with superconducting $^1\text{S}_0$ protons. In this contribution, we outline our theoretical framework and report tentative results showing how shape of quantum vortices could be affected by the presence of a proton fluxtube.