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Proceedings Paper

Walking on ratchets: a model of two Brownian motors with bistable coupling
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Paper Abstract

We propose a model for a walker moving on an asymmetric periodic ratchet potential. The walker has two 'feet' represented as two finite-size particles coupled nonlinearly through a double-well potential. In contrast to linear coupling, the bistable potential admits a richer dynamics where the ordering of the particles can alternate. The transitions between the two stable points on the bistable potential, correspond to a walking with alternating particles. In our model, each particle is acted upon by independent white noises, modeling thermal noise, and additionally we have an external time-dependent force that drives the system out of equilibrium, allowing directed transport. This force can be common colored noise, periodic deterministic driving or fluctuations on the bistable potential. In the equilibrium case, where only white noise is present, we perform a bifurcation analysis which reveals different walking patterns available for various parameter settings. Numerical simulations showed the existence of current reversals and significant changes in the effective diffusion constant and in the synchronization index. We obtained an optimal coherent transport, characterized by a maximum dimensionless ratio of the current and the effective diffusion (Peclet number), when the periodicity of the ratchet potential coincides with the equilibrium distance between the two particles.

Paper Details

Date Published: 7 May 2003
PDF: 12 pages
Proc. SPIE 5114, Noise in Complex Systems and Stochastic Dynamics, (7 May 2003); doi: 10.1117/12.497320
Show Author Affiliations
Jose L Mateos, Univ. Nacional Autonoma de Mexico (Mexico)
Alexander B Neiman, Univ. of Missouri/St. Louis (United States)
Frank E Moss, Univ. of Missouri/St. Louis (United States)
Jan A Freund, Humboldt-Univ. zu Berlin (Germany)
Lutz Schimansky-Geier, Humboldt-Univ. zu Berlin (Germany)
Igor M Sokolov, Humboldt-Univ. zu Berlin (Germany)

Published in SPIE Proceedings Vol. 5114:
Noise in Complex Systems and Stochastic Dynamics
Lutz Schimansky-Geier; Derek Abbott; Alexander Neiman; Christian Van den Broeck, Editor(s)

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