Tuning the Critical Current in Toroidal Superfluids via Controllable Impurities

TL;DR

This study investigates how controllable impurities influence the maximum superflow in toroidal Bose-Einstein condensates, revealing that impurity density can precisely tune supercurrent stability and decay mechanisms.

Contribution

It introduces combined numerical and experimental methods to control superflow stability through impurity density in atomic superfluids, highlighting vortex dynamics as key to supercurrent decay.

Findings

Impurity density controls superflow stability.

Vortex pinning and unpinning govern decay timescales.

Atomic superfluids serve as platforms for studying superflow mechanisms.

Abstract

We combine numerical and experimental approaches to study how impurities affect the maximum superflow in an annular Bose-Einstein condensate. By tuning the impurity density, we achieve precise control over the stability of persistent currents which increases with the impurity number. In the unstable regime, the complex vortex motion within the impurity landscape, characterized by pinning and unpinning events, governs the timescale of the current decay and its final value. Our work establishes atomic superfluids as a pristine platform for exploring universal mechanisms of superflow stabilization and decay, paving the way for atomtronic quantum technologies.