Cooperative rectification in confined Brownian ratchets

TL;DR

This paper investigates how confinement and ratchet mechanisms cooperate to induce directed Brownian motion, enabling transport and segregation in nanostructures through combined rectification effects.

Contribution

It reveals the emergence of cooperative rectification between ratchet effects and entropic confinement, leading to novel transport phenomena in confined Brownian systems.

Findings

Net particle transport can occur without individual ratchet or confinement effects.

Transport direction depends on particle size, enabling segregation.

Mechanism applicable to controlling transport in nanodevices.

Abstract

We analyze the rectified motion of a Brownian particle in a confined environment. We show the emergence of strong cooperativity between the inherent rectification of the ratchet mechanism and the entropic bias of the fluctuations caused by spatial confinement. Net particle transport may develop even in situations where separately the ratchet and the geometric restrictions do not give rise to particle motion. The combined rectification effects can lead to bidirectional transport depending on particle size, resulting in a new route for segregation. The reported mechanism can be used to control transport in mesostructures and nanodevices in which particles move in a reduced space.