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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.10: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Experimental Observation of Stochastic Resonance in Coupled Systems — •Tobias Sawetzki, Carmen Schmitt, and Clemens Bechinger — 2. Physikalisches Institut, Universität Stuttgart

Since the introduction of the concept of Stochastic Resonance (SR) for the description of the periodic occurrence of ice ages, SR has been found in a great variety of examples in nature (e.g. the feeding behavior of paddlefish or human balance control) and experiments (Schmitt triggers, ring lasers). The essential feature of SR is that in nonlinear systems the presence of a certain level of noise can improve the detection of weak periodic signals.

We investigate SR by observing the motion of a colloidal particles in a modulated double well potential, which is generated by two neighboring optical traps. By adding further double well potentials in a square geometry, we study the effect of coupling between the different systems. If the modulation signals for the double wells are in phase, we observe two effects: (i) SR is enhanced compared to the isolated system and (ii) with increasing coupling the resonance is shifted towards smaller frequencies. When a phase shift is between the modulations in the square, coupling results in an asymmetry in the pobability distribution.