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P. S.?Burada G.?Schmid D.?Reguera J. M.?Rubi P.?H?nggi 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(1):11-18
We demonstrate the existence of stochastic resonance (SR)
in confined systems arising from entropy variations associated to
the presence of irregular boundaries. When the motion of a Brownian
particle is constrained to a region with uneven boundaries, the
presence of a periodic input may give rise to a peak in the spectral
amplification factor and therefore to the appearance of the SR
phenomenon. We have proved that the amplification factor depends on
the shape of the region through which the particle moves and that by
adjusting its characteristic geometric parameters one may optimize
the response of the system. The situation in which the appearance of
such entropic stochastic resonance (ESR) occurs is common for
small-scale systems in which confinement and noise play an prominent
role. The novel mechanism found could thus constitute an important
tool for the characterization of these systems and can put to use
for controlling their basic properties. 相似文献
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Entropic splitter for particle separation 总被引:1,自引:0,他引:1
We present a particle separation mechanism which induces the motion of particles of different sizes in opposite directions. The mechanism is based on the combined action of a driving force and an entropic rectification of the Brownian fluctuations caused by the asymmetric form of the channel along which particles proceed. The entropic splitting effect shown could be controlled upon variation of the geometrical parameters of the channel and could be implemented in narrow channels and microfluidic devices. 相似文献
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Burada PS Schmid G Reguera D Vainstein MH Rubi JM Hänggi P 《Physical review letters》2008,101(13):130602
We present a novel scheme for the appearance of stochastic resonance when the dynamics of a Brownian particle takes place in a confined medium. The presence of uneven boundaries, giving rise to an entropic contribution to the potential, may upon application of a periodic driving force result in an increase of the spectral amplification at an optimum value of the ambient noise level. The entropic stochastic resonance, characteristic of small-scale systems, may constitute a useful mechanism for the manipulation and control of single molecules and nanodevices. 相似文献
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P. Sekhar Burada Dr. Peter Hänggi Prof. Dr. Dr. h.c. mult. Fabio Marchesoni Prof. Dr. Gerhard Schmid Dr. Peter Talkner Prof. Dr. 《Chemphyschem》2009,10(1):45-54
Diffusive transport of particles or, more generally, small objects, is a ubiquitous feature of physical and chemical reaction systems. In configurations containing confining walls or constrictions, transport is controlled both by the fluctuation statistics of the jittering objects and the phase space available to their dynamics. Consequently, the study of transport at the macro‐ and nanoscales must address both Brownian motion and entropic effects. Herein we report on recent advances in the theoretical and numerical investigation of stochastic transport occurring either in microsized geometries of varying cross sections or in narrow channels wherein the diffusing particles are hindered from passing each other (single‐file diffusion). For particles undergoing biased diffusion in static suspension media enclosed by confining geometries, transport exhibits intriguing features such as 1) a decrease in nonlinear mobility with increasing temperature or also 2) a broad excess peak of the effective diffusion above the free diffusion limit. These paradoxical aspects can be understood in terms of entropic contributions resulting from the restricted dynamics in phase space. If, in addition, the suspension medium is subjected to external, time‐dependent forcing, rectification or segregation of the diffusing Brownian particles becomes possible. Likewise, the diffusion in very narrow, spatially modulated channels is modified via contact particle–particle interactions, which induce anomalous sub‐diffusion. The effective sub‐diffusion constant for a driven single file also develops a resonance‐like structure as a function of the confining coupling constant. 相似文献
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