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DY: Dynamik und Statistische Physik

DY 51: Einstein Symposium Brownian Motion, Diffusion and Beyond (SYBM) – Contributed Talks II

DY 51.12: Talk

Wednesday, March 9, 2005, 13:00–13:15, TU H2032

From Sub- to Superthreshold Oscillations in Ensembles of Globally Coupled Excitable Systems — •Xaver Sailer¹, Michael Zaks¹, Alexander Neimann² und Lutz Schimansky-Geier¹ — ¹Institut fuer Physik, Newtonstrasse 15, 10119 Berlin — ²Institute of Physics and Astronomy, Ohio University, Athens, Ohio

We investigate a globally coupled ensemble of excitable FitzHugh-Nagumo systems subject to Gaussian white noise. In a certain parameter regime we find for increasing noise intensity a transition from a stable fixed point to global oscillations. The transition is complex and we find different regimes exhibiting small amplitude oscillations, period doubling, chaos, and intermittent and non-intermittent spiking. We derive the dynamical system of the ensembles moment dynamics in the Gaussian approximation and calculate the Hopf bifurcation condition analytically.