Asymmetric noise probed with a Josephson junction

TL;DR

This paper investigates how asymmetric current noise influences Josephson junction switching behavior, revealing effects of noise cumulants and comparing experimental results with theoretical models.

Contribution

It provides the first experimental measurement of the impact of noise asymmetry (third cumulant) on Josephson junction switching rates.

Findings

Asymmetric noise affects switching rates differently for opposite current directions.

The third cumulant causes measurable differences in switching behavior.

Results align quantitatively with recent theoretical predictions.

Abstract

Fluctuations of the current through a tunnel junction are measured using a Josephson junction. The current noise adds to the bias current of the Josephson junction and affects its switching out of the supercurrent branch. The experiment is carried out in a regime where switching is determined by thermal activation. The variance of the noise results in an elevated effective temperature, whereas the third cumulant, related to its asymmetric character, leads to a difference in the switching rates observed for opposite signs of the current through the tunnel junction. Measurements are compared quantitatively with recent theoretical predictions.