Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Nonlinear stochastic systems

DY 30.2: Talk

Friday, February 29, 2008, 10:30–10:45, MA 001

Controlling the coherence resonance in an excitable model exhibiting a global bifurcation — •Roland Aust, Johanne Hizanidis, and Eckehard Schöll — Institut f. Theor. Physik, Sekr. EW 7-1, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany

We examine a generic model [1] exhibiting a global bifurcation, namely a saddle-node bifurcation on a limit cycle (SNIPER) under the influence of Gaussian white noise and time-delayed feedback control. It was shown earlier [2] that the delayed feedback itself is able to induce multistability in the system. Here we study the interaction between noise and time-delayed feedback. In the whole control-parameter plane the existence of coherence resonance can be confirmed. By varying the system’s parameters we are able to choose the governing dynamics. In the regime where noise excites the system, the resulting oscillations can be controlled by the delayed feedback. We demonstrate the enhancement of coherence resonance by examining characteristic measures like the power spectral density and the correlation time. We also show how control enhances the regularity of the system’s oscillations, and in which way noise affects the delay-induced oscillations in the multistability regime.

[1] G. Hu, T. Ditzinger, C. Z. Ning and H. Haken, Stochastic resonance without external periodic force, Phys. Rev. Lett. 71, 807 (1993)

[2] J. Hizanidis, R. Aust and E. Schöll, Delay-induced multistability near a global bifurcation, Int. J. Bif. Chaos (2008), in print.