Mechanical Analogs of Time Dependent Josephson Phenomena

The pendulum analog of a small-area Josephson junction between two superconductors is coupled to the analogs of other circuit elements to demonstrate a variety of time dependent phenomena observed with actual devices. The analogy between electrical circuit and mechanical device is established through a Lagrangian formalism. The analog provides a simple and quick means of developing physical insight into this highly nonlinear system. To demonstrate the value of the analog we consider, as one example, the problem of a junction coupled to a resonant cavity and present a result that was missed by a previous solution.