Feedback and Rate Asymmetry of the Josephson Junction Noise Detector

TL;DR

This paper investigates the feedback effects in a Josephson junction noise detector, revealing how nonlinearity influences noise measurement asymmetries and predicting sign changes in rate asymmetry near specific voltages.

Contribution

It provides a detailed analysis of feedback mechanisms in Josephson junction noise detection and offers predictions for nonlinear device behavior.

Findings

Feedback significantly affects noise measurement asymmetry.

Strong nonlinearity leads to pronounced feedback effects.

Rate asymmetry can change sign near twice the superconducting gap.

Abstract

The Josephson junction noise detector measures the skewness of non-Gaussian noise via the asymmetry of the rate of escape from the zero-voltage state upon reversal of the bias current. The feedback of this detector on the noise generating device is investigated in detail. Concise predictions are made for a second Josephson junction as noise generating device. The strong nonlinearity of this component implies particularly strong feedback effects, including a change of sign of the rate asymmetry as the applied voltage approaches twice the superconducting gap.