Realizing an Atomtronic AQUID in a Rotating-Box Potential

TL;DR

This paper proposes and numerically investigates a novel atomtronic AQUID using a Bose-Einstein condensate in a rotating box potential, demonstrating quantized phase winding and flux-like response similar to electronic SQUIDs.

Contribution

It introduces a new implementation of an atomtronic AQUID based on a rotating box potential with a central barrier, expanding the design options for atomtronic quantum interference devices.

Findings

Quantized phase winding increases in discrete steps with angular velocity.

Centrifugal effects impair phase coherence but can be mitigated by harmonic confinement.

Density imbalance exhibits periodic dependence on angular velocity, analogous to SQUID voltage-flux relation.

Abstract

Atomtronic devices are matter-wave circuits designed to emulate the functional behavior of their electronic counterparts. Motivated by superconducting quantum interference devices (SQUIDs), atomic quantum interference devices (AQUIDs) have been developed using Bose-Einstein condensates (BECs) confined in toroidal geometries. Here, we propose and numerically investigate an alternative implementation of an AQUID based on a BEC confined in a rotating box potential. A ring-like topology is established by introducing a central depletion region via a repulsive potential barrier. We observe the hallmark AQUID feature -- quantized phase winding that increases in discrete steps with angular velocity. Centrifugal effects induced by rotation degrade phase coherence and impair AQUID performance, which we mitigate by applying a counteracting harmonic confinement. Phase slips are found to be mediated by a vortex propagating from the central depletion zone to the edge of the condensate. To characterize the voltage response, we induce a bias current by translating the box along its long axis while keeping the central barrier fixed. This generates a density imbalance between the two reservoirs, exhibiting a periodic dependence on angular velocity -- analogous to the voltage-flux relation in electronic SQUIDs. Our results demonstrate that rotating box geometries provide a viable and flexible platform for realizing atomtronic AQUIDs with controllable dynamics and well-defined response characteristics.