Analysis of soliton dynamics and noise induced effects on the superconductive lifetime in long Josephson junctions.

The influence of various noise sources on the transient dynamics of long Josephson junctions (LJJ) is investigated in the presence of an oscillating bias current signal and a noise source with Gaussian or non-Gaussian (i.e. Cauchy-Lorentz or Lévy-Smirnov) probability distributions. These systems are computationally analyzed integrating the perturbed Sine-Gordon equation describing the phase evolution. We found evidence of noise induced effects on trends of the mean escape time (MET) from the superconductive metastable state, varying different system parameters, as the bias frequency, noise intensity and junction length. In particular, we find resonant activation (RA) and noise enhanced stability (NES), and we study the connections between these phenomena and the creation/evolution of solitons (i.e. kink and antikink solutions) in the LJJ phase string dynamics. Pronounced changes in RA and NES are observed by using Lévy noise sources with different statistics. MET is also studied considering spatially homogeneous and inhomogeneous bias current distributions. In the latter case, in the presence of Gaussian noise, we observe an enhanced non-monotonic behavior, that, conversely, almost vanishes using noise sources with different statistics.