Fabio Marchesoni

Diffusive transport of particles or, more generally, small objects, is a ubiquitous feature of physical and chemical reaction systems [1]. 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. We report on recent advances in the theoretical and numerical investigation of stochastic transport occurring in microsized geometries where the “entropic channel” paradigm does not apply. 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 and 2) a broad excess diffusion peak or even Taylor diffusion depending on the channel geometry [1]. If, in addition, the suspended particles are subjected to external, time-dependent forcing, phenomena like anomalous negative mobility and geometric stochastic resonance may also occur.

[1] P. Hänggi and F. Marchesoni, Rev. Mod. Phys. 81, 387 (2009)