Quantum vortex reconnections

TL;DR

This paper investigates quantum vortex reconnections using numerical simulations of the Gross-Pitaevskii equation and vortex filament models, revealing different scaling behaviors and symmetry properties, and compares findings with superfluid helium experiments.

Contribution

It provides a comparative analysis of vortex reconnection dynamics between the Gross-Pitaevskii model and the Biot-Savart law, highlighting the role of radiation and symmetry in reconnection processes.

Findings

Minimum vortex separation scales differently before and after reconnection in the GP model.

Reconnections are time-symmetric in the Biot-Savart vortex filament model.

Radiation effects cause differences between the GP and Biot-Savart models.

Abstract

We study reconnections of quantum vortices by numerically solving the governing Gross-Pitaevskii equation. We find that the minimum distance between vortices scales differently with time before and after the vortex reconnection. We also compute vortex reconnections using the Biot-Savart law for vortex filaments of infinitesimal thickness, and find that, in this model, reconnection are time-symmetric. We argue that the likely cause of the difference between the Gross-Pitaevskii model and the Biot-Savart model is the intense rarefaction wave which is radiated away from a Gross-Pitaeveskii reconnection. Finally we compare our results to experimental observations in superfluid helium, and discuss the different length scales probed by the two models and by experiments.