PERTURBED PERIOD-DOUBLING BIFURCATION .2. EXPERIMENTS ON JOSEPHSON-JUNCTIONS

We present experimental results on the effect of periodic perturbations on a driven, dynamic system that is close to a period-doubling bifurcation. In the preceding article a scaling law for the change of stability of such a system was derived for the case where the perturbation frequency S is close to the resonances given by S/D=(1/2, 3) / 2, (5/2,..., where D is the driving frequency. The theoretical prediction for the shift of the bifurcation point, B, which we use as a measure of the stabilization, is BAS2, where AS is the perturbation amplitude. We have investigated B as a function of the frequency and the amplitude of the perturbation signal B(S,AS) for a model system, the microwave-driven Josephson tunnel junction, and find reasonable agreement between the experimental results and the theory. © 1990 The American Physical Society.