Dissipation Mechanisms in Fermionic Josephson Junction

TL;DR

This paper numerically investigates the dissipation mechanisms in a fermionic superfluid Josephson junction, identifying distinct processes like phase-slippage and pair-breaking across interaction regimes, enhancing understanding of superfluid dynamics.

Contribution

It provides a detailed numerical characterization of dissipation mechanisms in fermionic Josephson junctions across different interaction strengths, highlighting the physical origins of dissipation.

Findings

Dissipation in the strongly interacting regime occurs via phase-slippage with vortex emission.

In the weakly interacting regime, pair-breaking is the main dissipation channel.

Qualitative global dynamics are weakly sensitive to the specific dissipative mechanism.

Abstract

We characterize numerically the dominant dynamical regimes in a superfluid ultracold fermionic Josephson junction. Beyond the coherent Josephson plasma regime, we discuss the onset and physical mechanism of dissipation due to the superflow exceeding a characteristic speed, and provide clear evidence distinguishing its physical mechanism across the weakly- and strongly-interacting limits, despite qualitative dynamics of global characteristics being only weakly sensitive to the operating dissipative mechanism. Specifically, dissipation in the strongly interacting regime occurs through the phase-slippage process, caused by the emission and propagation of quantum vortices, and sound waves -- similar to the Bose-Einstein condensation limit. Instead, in the weak interaction limit, the main dissipative channel arises through the pair-breaking mechanism.