Quantum Dynamics of Small Josephson Junctions

Abstract

The general microscopic theory of “secondary” quantum effects in small superconducting tunnel junctions is proposed. Both linear (due to the Ohmic shunt) and “cosine” (due to the quasiparticle tunneling) dissipation mechanisms are considered. Quantum diffusion in the quasicharge space may be caused either by Cooper-pair tunneling or by single-electron tunneling (SET) for low temperature and bias. Quantum corrections to the classical Ohmic resistance are calculated for both cases. Coherent oscillations of the voltage (both Bloch and SET oscillations and also their coexistence) and current-voltage characteristics are studied for all parameter regions of interest. © 1987 The Japan Society of Applied Physics.