Transport in Superfluid Mixtures

TL;DR

This paper develops a comprehensive effective field theory framework for non-relativistic superfluid mixtures, revealing novel transport phenomena like Hall drag and velocity-dependent pinning, with geometric insights and a simple model demonstration.

Contribution

It generalizes existing superfluid theories to multiple components, introducing a geometric interpretation of transport effects and a model illustrating Hall drag in mixtures.

Findings

Discovery of parity odd Hall drag in superfluid mixtures

Identification of velocity-dependent pinning effects

Geometric interpretation using velocity polyhedra

Abstract

We present a general method for constructing effective field theories for non-relativistic superfluids, generalizing the previous approaches of Greiter, Witten, and Wilczek, and Son and Wingate to the case of several superfluids in solution. We investigate transport in mixtures with broken parity and find a parity odd "Hall drag" in the presence of independent motion as well as a pinning of mass, charge, and energy to sites of nonzero relative velocity. Both effects have a simple geometric interpretation in terms of the signed volumes and directed areas of various sub-complexes of a "velocity polyhedron": the convex hull formed by the endpoints of the velocity vectors of a superfluid mixture. We also provide a simple quasi-one-dimensional model that exhibits non-zero Hall drag.