Escape oscillations of a Josephson junction switching out of the zero-voltage state

The lifetime of the zero-voltage state of a current-biased Josephson junction shunted by a transmission line has been measured in the thermal regime. As the length of the line is increased in situ, the lifetime is modulated in an oscillatory pattern. The amplitude, period, phase, and tailing off of the modulation is the first direct evidence for the oscillations of the particle in the well before escape which are implied by Kramer’s energy-diffusion model for the escape from a metastable state.