Structure of surface vortex sheet between two rotating 3He superfluids

TL;DR

This paper investigates the structure of a surface vortex sheet formed at the interface between two different superfluid phases of helium-3, combining theoretical calculations with experimental NMR measurements.

Contribution

It introduces a detailed model of the surface vortex sheet structure, highlighting the formation of half-quantum units independent of bulk vorticity.

Findings

The vortex sheet structure is consistent with NMR measurements.

Vorticity compresses from three to two dimensions at the interface.

The vortex sheet consists of half-quantum units.

Abstract

We study a two-phase sample of superfluid 3He where vorticity exists in one phase (3He-A) but cannot penetrate across the interfacial boundary to a second coherent phase (3He-B). We calculate the bending of the vorticity into a surface vortex sheet on the interface and solve the internal structure of this new type of vortex sheet. The compression of the vorticity from three to two dimensions enforces a structure which is made up of half-quantum units, independently of the structure of the source vorticity in the bulk. These results are consistent with our NMR measurements.