Switching times in long-overlap Josephson junctions subject to thermal fluctuations and non-Gaussian noise sources

TL;DR

This paper studies how thermal and non-Gaussian noise influence the switching times and superconducting lifetime of long Josephson junctions, revealing complex nonmonotonic behaviors linked to soliton dynamics and noise effects.

Contribution

It introduces a detailed analysis of non-Gaussian noise effects on Josephson junction switching, highlighting the role of soliton dynamics and bias current distributions.

Findings

Mean lifetime exhibits nonmonotonic dependence on noise intensity and frequency.

Soliton formation and propagation significantly affect switching behavior.

Observed phenomena include stochastic resonant activation and noise-enhanced stability.

Abstract

We investigate the superconducting lifetime of long current-biased Josephson junctions, in the presence of Gaussian and non-Gaussian noise sources. In particular, we analyze the dynamics of a Josephson junction as a function of the noise signal intensity, for different values of the parameters of the system and external driving currents. We find that the mean lifetime of the superconductive state is characterized by nonmonotonic behavior as a function of noise intensity, driving frequency and junction length. We observe that these nonmonotonic behaviours are connected with the dynamics of the junction phase string during the switching towards the resistive state. An important role is played by the formation and propagation of solitons, with two different dynamical regimes characterizing the dynamics of the phase string. Our analysis allows to evidence the effects of different bias current densities, that is a simple spatially homogeneous distribution and a more realistic inhomogeneous distribution with high current values at the junction edges. Stochastic resonant activation, noise enhanced stability and temporary trapping phenomena are observed in the system investigated.