Stochastic resonance in colloidal systemsD. Babic1, 2, C. Schmitt1, I. Poberaj2 and C. Bechinger1
1 2. Physikalisches Institut, Universität Stuttgart Pfaffenwaldring 57, 70550 Stuttgart, Germany
2 Faculty of Mathematics and Physics, University of Ljubljana Jadranska 19, 1000 Ljubljana, Slovenia
(Received 25 March 2004; accepted in final form 5 May 2004)
We investigate the dynamical properties of a colloidal particle in a double-well potential which is periodically modulated in time. In case of the modulation corresponding to a tilt of the potential (asymmetric modulation), stochastic resonance is observed when the modulation frequency matches one half of the Kramers frequency of the unperturbed potential. In contrast, when only the potential barrier height is modulated (symmetric modulation), no synchronization between the modulation and the particle dynamics is observed as demonstrated by the lack of a peak in the power spectrum at .
02.50.Ey - Stochastic processes.
05.40.Jc - Brownian motion.
82.70.Dd - Colloids.
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