Switching Current Distributions in Josephson Junctions at Low Temperatures Resulting From Noise Enhanced Thermal Activation

TL;DR

This paper demonstrates that residual noise at low temperatures can significantly enhance thermal activation in Josephson junctions, explaining deviations from classical theory observed experimentally.

Contribution

It introduces the idea that minimal residual noise can account for low-temperature switching current distributions in Josephson junctions, aligning theory with experimental data.

Findings

Residual noise can increase escape rates at low temperatures.

Enhanced thermal activation explains deviations from classical models.

The model matches published experimental data.

Abstract

Experiments on the distributions of switching currents in Josephson junctions are sensitive probes of the mechanism by which a junction changes abruptly to a finite voltage state. At low temperatures data exhibit smooth and gradual deviations from the expectations of the classical theory of thermal activation over the barrier in the tilted washboard potential. In this paper it is shown that if a very small proportion of the noise energy entering the apparatus at room temperature survives filtering and reaches the sample, it can enhance the escape rate sufficiently to replicate experimental observations of the temperature dependence of the switching bias. This conjecture is successfully tested against published experimental data.