A channel Brownian pump powered by an unbiased external force

TL;DR

This paper investigates a Brownian pump in an asymmetric tube driven by an unbiased external force, revealing optimal conditions for maximum particle transport and how geometric factors influence efficiency.

Contribution

It introduces a model of a Brownian pump driven by unbiased forces in an asymmetric tube, analyzing how temperature and geometry affect pumping capacity.

Findings

Maximum pumping occurs at an optimal temperature or force amplitude.

Pumping can move particles against concentration gradients.

Pumping efficiency decreases with larger bottleneck radius.

Abstract

A Brownian pump of particles in an asymmetric finite tube is investigated in the presence of an unbiased external force. The pumping system is bounded by two particle reservoirs. It is found that the particles can be pumped through the tube from a reservoir at low concentration to one at the same or higher concentration. There exists an optimized value of temperature (or the amplitude of the external force) at which the pumping capacity takes its maximum value. The pumping capacity decreases with increasing the radius at the bottleneck of the tube.