A Josephson junction as a detector of Poissonian charge injection

TL;DR

This paper introduces a method using a hysteretic Josephson junction as a detector to measure the non-Gaussian, Poissonian charge injection noise by transforming charge statistics into current signals within a resonant circuit.

Contribution

It proposes a novel scheme employing a Josephson junction in the MQT regime as a noise detector for non-Gaussian charge statistics, with a detailed model of the measurement process.

Findings

The detector can sample charge injection statistics over a specific time window.

The scheme can reveal the Poisson character of charge injection with realistic parameters.

The model demonstrates the feasibility of detecting non-Gaussian noise using Josephson junctions.

Abstract

We propose a scheme of measuring the non-Gaussian character of noise by a hysteretic Josephson junction in the macroscopic quantum tunnelling (MQT) regime. We model the detector as an (under)damped $LC$ resonator. It transforms Poissonian charge injection into current through the detector, which samples the injection statistics over a floating time window of length $\sim Q/\omega _{\rm J}$, where $Q$ is the quality factor of the resonator and $\omega_{\rm J}$ its resonance frequency. This scheme ought to reveal the Poisson character of charge injection in a detector with realistic parameters.