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DY: Dynamik und Statistische Physik

DY 11: Nonlinear Dynamics

DY 11.5: Vortrag

Freitag, 4. März 2005, 11:30–11:45, TU H2032

Stochastic Resonance in Colloidal Systems — •Carmen Schmitt¹, Dusan Babic², Igor Poberaj², and Clemens Bechinger¹ — ¹2. Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart — ²Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia

The concept of Stochastic Resonance (SR) has been used to describe very different effects such as the periodic occurence of the ice ages, the feeding behaviour of paddlefish or human balance control and visual perception. The essential feature of SR is that in nonlinear systems noise can improve the detection of weak periodic signals.

Although characteristic features of SR have been observed in several experiments, there are only few examples where the effect is studied on a microscopic level. In our experiment we work with a model system where both the length scales and the time scales are conveniently accessible: we investigate the dynamics of colloidal particles fluctuating in double well potentials created by optical tweezers. In contrast to many other experiments, this configuration allows us to study systems of several coupled particles.

We present results on SR in an isolated system [1] and in systems with several coupled particles.

[1] D. Babič, C. Schmitt, I. Poberaj and C. Bechinger, Europhys. Lett. 67, 158–164 (2004)