Shot-noise governed Coulomb blockade in a single Josephson junction

TL;DR

This paper demonstrates how shot noise influences Coulomb blockade in a single Josephson junction, showing that shot noise suppresses the Cooper pair current blockade and can be used to detect very low current levels.

Contribution

It extends phase correlation theory to account for shot noise effects in a Josephson junction, revealing its impact on Coulomb blockade phenomena.

Findings

Shot noise suppresses Coulomb blockade in the Josephson junction.

The effective noise temperature T_N characterizes shot noise influence.

Josephson junctions can detect shot noise from currents below 1 pA.

Abstract

We have investigated the influence of shot noise on the IV-curves of a single mesoscopic Josephson junction. We find that the blockade of the Cooper pair current is strongly suppressed in the presence of shot noise due to tunnelling in an adjacent SIN junction. Our experimental findings can be accounted for by an extension of the phase correlation theory. Shot-noise effect in a resistive environment R can be characterized by the effective noise temperature T_N = eIR /2 k_B, which means that a Josephson junction can easily detect shot noise from a current well below 1 pA.