Modeling Josephson junctions

The current-voltage characteristic of a current-biased junction is calculated using the Werthamer theory. In contrast with the voltage-biased model large zero-frequency currents exist at 0°K at all bias voltages below the energy gap and the Riedel peak is directly displayed. The effect of capacitance on the $I-V$ curve is described and the form of the subharmonic energy-gap structure is calculated using the Mattis-Bardeen model for the superconducting electrodes.