STABILITY OF THE ZERO-VOLTAGE STATE IN LONG JOSEPHSON-JUNCTIONS COUPLED TO A MICROWAVE RESONATOR

We are investigating the amplitude of the dc Josephson current in long Josephson junctions coupled to a stripline rf resonator by a thin fil m capacitor. In this experiment the junction is driven by an rf signal in the X-band and the dc critical current vs. the microwave power is recorded for different values of the external dc magnetic field. We fi nd that the height of the dc critical current depends strongly on the relative polarities of the dc bias current and the external magnetic f ield. The phenomenon can be interpreted in terms of the Perturbed Sine Gordon Equation model.