Stochastic resonance and brownian ratchets
Stochastic resonance and brownian ratchets
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Fecha
2005
Autores
Fendrik, Alejandro J.
Romanelli, Lilia
Perazzo, Roberto P. J.
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"We discuss the connections between Brownian ratchets (BR) and stochastic resonance (SR). We consider a periodic potential energy landscape with no left–right symmetry that is driven
by an external force which can be derived from a potential that is periodic both in time and space. We show that this system presents two thermal enhancements within two different windows of the temperature. One is associated with a ‘‘coherent diffusion’’ by which particles jump back and forth between the minima of the periodic potential in synchrony with the external driving. The other is instead associated with a ‘‘coherent directional transport’’ by which particles hop synchronically from one minimum of the ratchet to the next. We calculate
the current and the diffusion coefficients and show how transport undergoes a resonant enhancement. While the former is always present, the second only appears when left–right symmetry is broken."