Clustering in delay-coupled smooth and relaxational chemical oscillators.
We investigate cluster synchronization in networks of nonlinear systems with time-delayed coupling. Using a generic model for a system close to the Hopf bifurcation, we predict the order of appearance of different cluster states and their corresponding common frequencies depending upon coupling delay. We may tune the delay time in order to ensure the existence and stability of a specific cluster state. We qualitatively and quantitatively confirm these results in experiments with chemical oscillators. The experiments also exhibit strongly nonlinear relaxation oscillations as we increase the voltage, i.e., go further away from the Hopf bifurcation. In this regime, we find secondary cluster states with delay-dependent phase lags. These cluster states appear in addition to primary states with delay-independent phase lags observed near the Hopf bifurcation. Extending the theory on Hopf normal-form oscillators, we are able to account for realistic interaction functions, yielding good agreement with experimental findings.
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22902, USA.
Karen
K
Blaha
Institut für Theoretische Physik, TU Berlin, Hardenbergstraße 36, 10623 Berlin, Germany.
Judith
J
Lehnert
Institut für Theoretische Physik, TU Berlin, Hardenbergstraße 36, 10623 Berlin, Germany.
Andrew
A
Keane
Institut für Theoretische Physik, TU Berlin, Hardenbergstraße 36, 10623 Berlin, Germany.
Thomas
T
Dahms
Institut für Theoretische Physik, TU Berlin, Hardenbergstraße 36, 10623 Berlin, Germany and Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, Germany.
Philipp
P
Hövel
Institut für Theoretische Physik, TU Berlin, Hardenbergstraße 36, 10623 Berlin, Germany.
Eckehard
E
Schöll
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22902, USA.
John L
JL
Hudson