Switching current distributions in Josephson junctions at very low temperatures

Swept bias experiments carried out on Josephson junctions yield the distributions of the probabilities of early switching from the zero-voltage state. Kramers’ theory of the thermally activated escape from a one-dimensional potential is well known to fall short of explaining such experiments when the junctions are at millikelvin temperatures. We propose a simple revision of the theory which is shown to give extremely good agreement with experimental data.