Communication: Impact of inertia on biased Brownian transport in confined geometries

Abstract

We consider the impact of inertia on biased Brownian motion of point-size particles in a two-dimensional channel with sinusoidally varying width. If the time scales of the problem separate, the adiabatic elimination of the transverse degrees of freedom leads to an effective description for the motion along the channel given by the potential of mean force. The possibility of such description is intimately connected with equipartition. Numerical simulations show that in the presence of external bias the equipartition may break down leading to non-monotonic dependence of mobility on external force and several other interesting effects.

How entropy and hydrodynamics cooperate in rectifying particle transport

“…We reveal that F(x) comprises the usual entropic contribution (the logarithmic term) [10,29] caused by the non-holonomic constraint stemming from the boundaries [18,30] and an additional, energetic contribution stemming from Ψ 0 [12]. In the absence of the flow field, i.e., for Ψ = 0, Eqs.…”

Rectified motion in an asymmetric channel: The role of hydrodynamic interactions with walls

“…An important category of micro-fluidic devices is so-called rocked ratchet, where an applied oscillating force drives a net drift velocity for particles fluctuating in an asymmetric potential * Electronic address: najafi@znu.ac.ir imposed by the walls of channel . The physical mechanism behind such systems has been considered in details [9,10]. A very comprehensive review of the related works is presented in an article by P. Hanggi [11].…”

Giant enhancement of hydrodynamically enforced entropic trapping in thin channels

“…The capability of such devices for separation of particles is rooted in the effect of entropic rectification, i.e., the rectification of motion caused by broken spatial symmetry caused by asymmetric variations of the accessible local volume [18][19][20]. The transport in channels with periodically varying cross-section exhibits peculiar transport phenomena [21][22][23][24][25][26] which can be treated by means of the so-termed Fick-Jacobs formalism and its generalizations [1,[27][28][29][30][31][32][33][34][35][36]. Figure 1.…”