Realizing and optimizing an atomtronic SQUID

TL;DR

This paper demonstrates how a toroidal Bose-Einstein condensate with a movable barrier can be used to realize an atomtronic SQUID, optimizing the barrier ramp-up protocol for better experimental control and understanding phase slip dynamics.

Contribution

It introduces an optimized ramp-up protocol for the barrier in an atomtronic SQUID and analyzes the effects of barrier height and ramping procedures on system coherence and phase slips.

Findings

Optimal barrier ramp-up protocol improves system stability.

Higher barriers suppress phase coherence due to thermal fluctuations.

Ramp-up and ramp-down time scales significantly affect system dynamics.

Abstract

We demonstrate how a toroidal Bose-Einstein condensate with a movable barrier can be used to realize an atomtronic SQUID. The magnitude of the barrier height, which creates the analogue of an SNS junction, is of crucial importance, as well as its ramp-up and -down protocol. For too low of a barrier, the relaxation of the system is dynamically suppressed, due to the small rate of phase slips at the barrier. For a higher barrier, the phase coherence across the barrier is suppressed due to thermal fluctuations, which are included in our Truncated Wigner approach. Furthermore, we show that the ramp-up protocol of the barrier can be improved by ramping up its height first, and its velocity after that. This protocol can be further improved by optimizing the ramp-up and ramp-down time scales, which is of direct practical relevance for on-going experimental realizations.