Quantization of Superflow Circulation and Magnetic Flux with a Tunable Offset

TL;DR

This paper explores how superflow circulation and magnetic flux quantization in systems with nonscalar order parameters can exhibit tunable offsets from integer values, revealing a form of Aharonov-Bohm physics.

Contribution

It demonstrates that in certain superfluid and superconductor systems, circulation and flux are quantized with a tunable offset, extending understanding of topological effects in these materials.

Findings

Circulation is related to anholonomy in order parameter transport.

Quantization can be nonintegral and tunably offset from integers.

Experimental setups are proposed to test these phenomena.

Abstract

Quantization of superflow-circulation and of magnetic-flux are considered for systems, such as superfluid $^3$He-A and unconventional superconductors, having nonscalar order parameters. The circulation is shown to be the anholonomy in the parallel transport of the order parameter. For multiply-connected samples free of distributed vorticity, circulation and flux are predicted to be quantized, but generically to nonintegral values that are tunably offset from integers. This amounts to a version of Aharonov-Bohm physics. Experimental settings for testing these issues are discussed.