Quasiparticle-induced coupling effects between two superconducting weak links

Abstract

Interactions between two independently biased thin-film superconducting microbridges yield a voltage step in the current-voltage characteristics of the bridges. Perturbation theory applied to the quasiparticle coupling currents explains these results as apparent critical current depression due to a regenerative feedback effect. Calculated changes in the critical current caused by the combined effects of order parameter depression, dc and ac quasiparticle coupling currents are in good agreement with experiments.