Chimera dynamics in nonlocally coupled bicomponent oscillators

The chimera state, characterized by the coexistence of coherent and incoherent domains, has become an active research field. In this work, we consider a ring of nonlocally coupled bicomponent FitzHugh-Nagumo oscillators by randomly partitioning oscillators into two groups with different epsilon, a parameter characterizing the separation of the time scale between activator and inhibitor in a FitzHugh-Nagumo oscillator. Through this way, we introduce heterogeneity into the model, which is measured by the mismatch of epsilon in the two groups. We find that there are two types of chimera dynamics, synchronous chimera state at weak mismatch between epsilon in the two groups and asynchronous chimera state at strong mismatch of epsilon, which is not sensitive to the partition of oscillators. The existence of asynchronous chimera state at strong mismatch of epsilon stands in contrast to the ordinary view that strong heterogeneity in non-identical oscillators is harmful to chimera state. By monitoring the effective frequencies of the coherent oscillators and the sizes of the coherent domains in the two groups, we find that the transition between the synchronous chimera state and the asynchronous chimera state is a discontinuous one. Copyright (C) 2021 EPLA