Potential Escape Dynamics for Very Underdamped Josephson Junctions

The demand for new concepts and devices operating at low temperature and very light dissipation require knowledge of the features of the washboard potential of Josephson junctions in parameter ranges that have never been considered up to now. We investigate systematically in particular the dynamics of the escape out its one-dimensional potential of the forced pendulum in the limit of very weak dissipation for relatively low, moderate or high sweep rate. The dependencies of the escape process upon the dissipation present in the system, on the rate at which the system is forced to escape out of the potential, and the noise (temperature) are throughout investigated. We find that initial conditions, in specific parameter plane regions and temperature ranges, influence strongly the escape according to a scenario which can be well characterized by specific combinations of the parameters. Our investigations are performed for both zero and non-zero temperature.