Taming of chaos and synchronisation in RCL-shunted Josephson junctions by external forcing

Abstract

The use of external forcing to influence the dynamics of RCL-shunted Josephson junction is reported either to control chaos or to synchronise two identical coupled junctions. The frequency of an external periodic signal is used as the control parameter for taming or suppressing chaos in a junction. Numerical investigations show that the junction oscillation is amplitude modulated at forcing frequencies much lower than the natural frequency of the junction. When the forcing frequency is increased to a higher range close to the natural frequency of the junction, phase locking (n : m) of the sinusoidal forcing is observed. Two important routes to chaos, period doubling and torus breakdown are observed as the forcing frequency range is changed. Synchronisation of two identical junctions is implemented using an external negative pulsing.