Observation of a superfluid Hall effect

TL;DR

This paper reports the first observation of a superfluid Hall effect in a Bose-Einstein condensate of neutral atoms, demonstrating the influence of superfluid properties on transverse transport under a synthetic magnetic field.

Contribution

It introduces the first experimental evidence of a Hall effect in a neutral superfluid, expanding the understanding of Hall phenomena beyond charged particle systems.

Findings

Hall effect observed in ultracold neutral atoms

Results agree with hydrodynamic predictions

Superfluid irrotationality affects Hall signal

Abstract

Measurement techniques based upon the Hall effect are invaluable tools in condensed matter physics. When an electric current flows perpendicular to a magnetic field, a Hall voltage develops in the direction transverse to both the current and the field. In semiconductors, this behaviour is routinely used to measure the density and charge of the current carriers (electrons in conduction bands or holes in valence bands) -- internal properties of the system that are not accessible from measurements of the conventional resistance. For strongly interacting electron systems, whose behaviour can be very different from the free electron gas, the Hall effect's sensitivity to internal properties makes it a powerful tool; indeed, the quantum Hall effects are named after the tool by which they are most distinctly measured instead of the physics from which the phenomena originate. Here we report the first observation of a Hall effect in an ultracold gas of neutral atoms, revealed by measuring a Bose-Einstein condensate's transport properties perpendicular to a synthetic magnetic field. Our observations in this vortex-free superfluid are in good agreement with hydrodynamic predictions, demonstrating that the system's global irrotationality influences this superfluid Hall signal.