A Josephson junction as a detector of Poissonian charge injection

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.