Geometric Laws of Vortex Quantum Tunneling

TL;DR

This paper investigates how geometric factors influence vortex quantum tunneling in superfluid Helium II, emphasizing the role of the tunneling volume and constraints like closest approach distance.

Contribution

It explicitly demonstrates the impact of geometry on tunneling volume and introduces a geometric constraint critical for the semiclassical description of vortex nucleation.

Findings

Geometry affects the tunneling volume in vortex quantum tunneling.

A minimum closest approach distance is necessary for semiclassical tunneling description.

Geometry dependence can be used to verify vortex tunneling experimentally.

Abstract

In the semiclassical domain the exponent of vortex quantum tunneling is dominated by a volume which is associated with the path the vortex line traces out during its escape from the metastable well. We explicitly show the influence of geometrical quantities on this volume by describing point vortex motion in the presence of an ellipse. It is argued that for the semiclassical description to hold the introduction of an additional geometric constraint, the distance of closest approach, is required. This constraint implies that the semiclassical description of vortex nucleation by tunneling at a boundary is in general not possible. Geometry dependence of the tunneling volume provides a means to verify experimental observation of vortex quantum tunneling in the superfluid Helium II.