Energy levels quantization in Josephson junctions

Abstract

We have measured the switching current distributions out of the zero-voltage state of Josephson junctions in nonstationary conditions, obtained by means of fast sweeping of the current bias (≌100 kHz) resulting in a dI/dt up to 25 A/s. In this way we have analysed the effects of the levels quantization on the escape rate out of the zero voltage state in conditions where the occupancy probability of the energy levels is far from being in equilibrium.