Bi-Josephson Effect in a Driven-Dissipative Supersolid

TL;DR

This paper investigates the bi-Josephson effect in a driven-dissipative supersolid, revealing how supersolid order influences Josephson currents and enabling potential new quantum device applications.

Contribution

It introduces the concept of a bi-Josephson effect in supersolids and analyzes how supersolid order affects Josephson currents and relationships.

Findings

Two types of DC Josephson currents depend on barrier location.

Supersolid order enhances one Josephson current type while suppressing the other.

Distinct Josephson physics emerge in the supersolid phase.

Abstract

The Josephson effect is a macroscopic quantum tunneling phenomenon in a system with superfluid property, when it is split into two parts by a barrier. Here, we examine the Josephson effect in a driven-dissipative supersolid realized by coupling Bose-Einstein condensates to an optical ring cavity. We show that the spontaneous breaking of spatial translation symmetry in supersolid makes the location of the splitting barrier have a significant influence on the Josephson effect. Remarkably, for the same splitting barrier, depending on its location, two different types of DC Josephson currents are found in the supersolid phase (compared to only one type found in the superfluid phase). Thus, we term it a bi-Josephson effect. We examine the Josephson relationships and critical Josephson currents in detail, revealing that the emergence of supersolid order affects these two types of DC Josephson currents differently -- one is enhanced, while the other is suppressed. The findings of this work unveil unique Josephson physics in the supersolid phase, and show new opportunities to build novel Josephson devices with supersolids.