Parametric resonance in small Josephson junctions in the presence of oscillating magnetic fields

Abstract

Comparing the stationary states of a mechanical pendulum and of a small under-damped Josephson junction, parametric resonance in the latter system due to an oscillating magnetic field is studied by means of a Gedanken-experiment. A second conceptual experiment shows that for rapidly oscillating magnetic fields the superconducting phase difference ϕ across the junction in the absence of bias current can attain values of ±π in the vicinity of the lower lying stationary state at ϕ=0.