Quantum vortex channels as Josephson junctions

TL;DR

This paper demonstrates that quantized vortices in rotating binary condensates can act as self-induced Josephson junctions, enabling superflow control and tunable weak links through interaction strength and dipolar effects.

Contribution

It introduces a novel mechanism where vortices form self-induced weak links in superfluids, with tunable properties driven by interspecies and dipolar interactions.

Findings

Vortices form hollow channels acting as weak links in superfluids.

Tuning interactions drives a crossover from hydrodynamic to Josephson tunneling.

Circuit models accurately describe the current-phase relations.

Abstract

In quantum gases, weak links are typically realized with externally imposed optical potentials. We show that, in rotating binary condensates, quantized vortices in one component form hollow channels that act as self-induced weak links for the other, enabling superflow through otherwise impenetrable, phase-separated domains. This introduces a novel barrier mechanism: quantum pressure creates an effective barrier inside the vortex channel, set by the constriction width, which controls the superflow. Tuning the interspecies interaction strength drives a crossover from the hydrodynamic transport to Josephson tunneling regime. Long-range dipolar interactions further tune the weak-link properties, enabling both short links and two coupled junctions in series. Circuit models quantitatively capture the dc current-phase relations for both configurations. These results establish vortices as reconfigurable, interaction-controlled Josephson elements in superfluids.