Dynamics of coreless vortices and rotation-induced dissipation peak in superfluid films on rotating porous substrates

TL;DR

This paper models the dynamics of coreless vortices in superfluid films on porous substrates, linking 3D vortex motion to 2D vortex-antivortex pair dissociation, explaining rotation-induced dissipation peaks observed experimentally.

Contribution

It introduces a theoretical framework connecting 3D vortex dynamics with 2D dissociation rates based on Kosterlitz-Thouless theory, explaining experimental dissipation peaks.

Findings

Vortex motion characterized as jumps between substrate cells

Derived vortex velocity from vortex-antivortex pair dissociation rates

Explains rotation-induced dissipation peaks in superfluid films

Abstract

We analyze dynamics of 3D coreless vortices in superfluid films covering porous substrates. The 3D vortex dynamics is derived from the 2D dynamics of the film. The motion of a 3D vortex is a sequence of jumps between neighboring substrate cells, which can be described, nevertheless, in terms of quasi-continuous motion with average vortex velocity. The vortex velocity is derived from the dissociation rate of vortex-antivortex pairs in a 2D film, which was developed in the past on the basis of the Kosterlitz-Thouless theory. The theory explains the rotation-induced dissipation peak in torsion-oscillator experiments on $^4$He films on rotating porous substrates and can be used in the analysis of other phenomena related to vortex motion in films on porous substrates.