Transition to complete synchronization and global intermittent synchronization in an array of time-delay systems

TL;DR

This paper investigates how arrays of time-delay systems transition from nonsynchronous to synchronized states, revealing different behaviors for unidirectional and mutual coupling, including a novel global intermittent synchronization phenomenon.

Contribution

It provides a detailed analysis of synchronization transitions in time-delay systems, introducing the concept of global intermittent synchronization and relating it to unstable periodic orbit theory.

Findings

Transition to CS varies with coupling configuration

Global intermittent synchronization observed during transition

Unstable periodic orbit theory explains synchronization behavior

Abstract

We report the nature of transitions from nonsynchronous to complete synchronization (CS) state in arrays of time-delay systems, where the systems are coupled with instantaneous diffusive coupling. We demonstrate that the transition to CS occurs distinctly for different coupling configurations. In particular, for unidirectional coupling, locally (microscopically) synchronization transition occurs in a very narrow range of coupling strength but for a global one (macroscopically) it occurs sequentially in a broad range of coupling strength preceded by an intermittent synchronization. On the other hand, in the case of mutual coupling a very large value of coupling strength is required for local synchronization and, consequently, all the local subsystems synchronize immediately for the same value of the coupling strength and hence globally synchronization also occurs in a narrow range of the coupling strength. In the transition regime, we observe a new type of synchronization transition where long intervals of high quality synchronization which are interrupted at irregular times by intermittent chaotic bursts simultaneously in all the systems, which we designate as global intermittent synchronization (GIS). We also relate our synchronization transition results to the above specific types using unstable periodic orbit theory. The above studies are carried out in a well known piecewise linear time-delay system.