Experimental observation of chimera and cluster states in a minimal globally coupled network

TL;DR

This study experimentally demonstrates chimera and cluster states in a minimal network of four globally coupled chaotic oscillators, revealing fundamental mechanisms of partial synchronization.

Contribution

First experimental observation of chimera and cluster states in a minimal four-oscillator network, providing new insights into their formation and stability.

Findings

Chimera states occur in minimal networks of four oscillators.

Chimera and cluster states are closely related phenomena.

Chimera states often appear in multistability regions.

Abstract

A "chimera state" is a dynamical pattern that occurs in a network of coupled identical oscillators when the symmetry of the oscillator population is broken into synchronous and asynchronous parts. We report the experimental observation of chimera and cluster states in a network of four globally coupled chaotic opto-electronic oscillators. This is the minimal network that can support chimera states, and our study provides new insight into the fundamental mechanisms underlying their formation. We use a unified approach to determine the stability of all the observed partially synchronous patterns, highlighting the close relationship between chimera and cluster states as belonging to the broader phenomenon of partial synchronization. Our approach is general in terms of network size and connectivity. We also find that chimera states often appear in regions of multistability between global, cluster, and desynchronized states.