Phase Fluctuations and Non-Equilibrium Josephson Effect

TL;DR

This paper investigates how non-equilibrium electron density fluctuations in a diffusive S-N-S junction suppress the Josephson current, revealing the impact of external bias on phase stability and supercurrent magnitude.

Contribution

It introduces a model linking non-equilibrium electron fluctuations to phase fluctuations, demonstrating their effect on Josephson current suppression.

Findings

Non-equilibrium fluctuations cause phase fluctuations in the S-layers.

Josephson current is significantly suppressed under non-equilibrium conditions.

Phase fluctuations are driven by external bias and electron density variations.

Abstract

We consider a diffusive S-N-S junction with electrons in the normal layer driven out of equilibrium by external bias. We show that, the non-equilibrium fluctuations of the electron density in the normal layer cause the fluctuations of the phase of the order parameter in the S-layers. As a result, the magnitude of the Josephson current in the non-equilibrium junction is significantly supressed relative to its mean field value.