A computational study of some Josephson junction circuits Original Research Article

An autonomous nonlinear dynamical system based upon a McCumber model of a Josephson junction has been studied by numerical and electronic simulations. The dynamical structure includes period doubling bifurcations leading to chaos and subharmonic phase locking leading to voltage steps apparently corresponding to fractional quantum effects. The Lyapunov spectrum is very rich, providing insight into the dynamics. It is emphasized that computational study can provide valuable results which are not accessible either from real experiments nor from analytic theory.