Synchronization of chaos in two mesoscopic shunted resistive–capacitive–inductive Josephson junctions by means of a nonlinear van der Pol oscillator

Abstract

A scheme for chaotic synchronization of two mesoscopic shunted resistive–capacitive–inductive Josephson junctions by means of a third common van der Pol oscillator (the master system) is presented in this paper. The output signal from the latter system in its highly nonlinear state is used to drive both junctions (the slave system). Our numerical calculations demonstrate that the junctions are in chaotic states (positive Lyapunov exponent) prior to being coupled to the master drive, and can be synchronized when they are in their periodic states. It is also revealed that the synchronization state of both junctions is controlled by the driving intensity and damping parameter of the van der Pol oscillator. The bifurcation from chaotic to periodic behaviour or vice versa occurs by altering the external dc bias current passing through the system. The complementary role of the damping parameter and the bias current in controlling synchronization is demonstrated.