Interdisciplinary Seminar in Nonlinear Science

Title: Noise-induced dynamics in bistable systems with delay
Speaker: Lev Tsimring, Institute for Nonlinear Science, University of California
Speaker Info: San Diego
Brief Description:
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In non-equilibrium systems, noise is known to produce surprising effects such as noise-induced phase transitions, stochastic resonance, etc. In this talk, we will consider noise-induced dynamics of a prototypical bistable system with delayed feedback. For small noise and magnitude of the feedback, the problem can be reduced to analysis of the two-state model with certain transition rates which depend on the earlier state of the system. In this two-state approximation, we find analytical formulae for the autocorrelation function, the power spectrum, and the linear response to a periodic perturbation. They show very good agreement with direct numerical simulations of the original Langevin equation. The power spectrum has a pronounced peak at the frequency corresponding to the inverse delay time, whose amplitude has a maximum at a certain noise level, thus demonstrating coherence resonance. The linear response to the external periodic force also has maxima at the frequencies corresponding to the inverse delay time and its harmonics.
Date: Friday, March 15, 2002
Time: 2:00PM
Where: Technological Institute M416
Contact Person: Paul Umbanhowar
Contact email: umbanhowar@northwestern.edu
Contact Phone: 847-7291
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