Josephson-like oscillations in toroidal spinor Bose-Einstein condensates: a prospective symmetry probe

TL;DR

This paper demonstrates Josephson-like oscillations in a toroidal spinor Bose-Einstein condensate, revealing a new way to probe spinor symmetry through superfluid current measurements in ultracold gases.

Contribution

It introduces a novel analogy between superconducting Josephson effects and superfluidity in spinor BECs, enabling symmetry probing via current oscillations.

Findings

Atomic current density oscillates without circulation through the barrier.

Broken-symmetry states alter the Josephson-like current structure.

Potential to use superfluid current measurements to probe spinor symmetry.

Abstract

Josephson junctions are essential ingredients in the superconducting circuits used in many existing quantum technologies. Additionally, ultracold atomic quantum gases have also become essential platforms to study superfluidity. Here, we explore the analogy between superconductivity and superfluidity to present an intriguing effect caused by a thin finite barrier in a quasi-one-dimensional toroidal spinor Bose--Einstein condensate (BEC). In this system, the atomic current density flowing through the edges of the barrier oscillates, such as the electrical current through a Josephson junction in a superconductor, but in our case, there is no current circulation through the barrier. We also show how the nontrivial broken-symmetry states of spinor BECs change the structure of this Josephson-like current, creating the possibility to probe the spinor symmetry, solely using measurements of this superfluid current.