Escape dynamics in a double periodic potential

We analyze, theoretically and by numerical simulations of the associated Langevin equation, the dynamics of thermal escape from a generalized washboard potential with a second harmonic term. This theory applies to novel superconducting devices, as the high-temperature superconductor devices or the superconductingferromagnetic-superconducting junctions, which appears to present a not negligible second harmonic term in the current-phase relation. The results show that the escape dynamics depends on the ratio between the amplitude of harmonics and the quality factor of the devices. Moreover, an interesting dependance is found in the sign of the second harmonic term: in some cases a positive term can be discriminated from a negative term by the temperature behavior of the escape current distributions.