Persistent current formation in double-ring geometries

TL;DR

This paper explores how persistent currents form in coupled double-ring geometries of ultracold bosonic gases, revealing independent winding behaviors and robustness against dissipation, with potential for experimental realization.

Contribution

It extends the understanding of persistent current formation from single rings to coupled double-ring and lemniscate geometries, highlighting independent winding number emergence.

Findings

Independent winding numbers can form in coupled rings.

Persistent currents are robust despite dissipative effects.

Flow directions can be the same or opposite in the rings.

Abstract

Quenching an ultracold bosonic gas in a ring across the Bose-Einstein condensation phase transition is known, and has been experimentally observed, to lead to the spontaneous emergence of persistent currents. The present work examines how these phenomena generalize to a system of two experimentally accessible explicitly two-dimensional co-planar rings with a common interface, or to the related lemniscate geometry, and demonstrates an emerging independence of winding numbers across the rings, which can exhibit flow both in the same and in opposite directions. The observed persistence of such findings in the presence of dissipative coupled evolution due to the local character of the domain formation across the phase transition and topological protection of the randomly emerging winding numbers should be within current experimental reach.