Interface dependence of the Josephson-current fluctuations in short SNS junctions

TL;DR

This paper investigates how the transparency of interfaces in short SNS junctions affects Josephson-current fluctuations, revealing a universal factor difference in correlations based on interface transparency.

Contribution

It introduces an effective field theory for mesoscopic SNS devices that accounts for interface transparency effects on Josephson-current correlations.

Findings

Two-point Josephson-current correlator differs by a factor of 2 depending on interface transparency.

The supersymmetry method is used to analyze the impact of interface transparency.

Universal behavior identified in the fluctuation correlations.

Abstract

We discuss the dependence of the Josephson current correlations in mesoscopic superconductor/normal-conductor/superconductor (SNS) devices on the transparency of the superconductor/normal-conductor (SN) interfaces. Focusing on short junctions we apply the supersymmetry method to construct an effective field theory for mesoscopic SNS devices which is evaluated in the limit of highly and weakly transparent interfaces. We show that the two-point Josephson-current correlator differs by an universal factor 2 in these two cases.