Transport and diffusion properties of Brownian particles powered by a rotating wheel

TL;DR

This study investigates how a rotating wheel influences the diffusion and directed transport of Brownian particles in a 2D channel, revealing optimal conditions for maximum diffusion and transport directionality.

Contribution

It introduces a numerical analysis of Brownian particle transport driven by a rotating wheel, highlighting the effects of system parameters on diffusion and velocity.

Findings

Transport direction depends on potential asymmetry and wheel position.

Average velocity peaks at specific angular speeds and shifts with system parameters.

Maximum effective diffusion occurs at distinct parameters from velocity maximum.

Abstract

Diffusion and rectification of Brownian particles powered by a rotating wheel are numerically investigated in a two-dimensional channel. The nonequilibrium driving comes from the rotating wheel, which can break thermodynamical equilibrium and induce the directed transport in an asymmetric potential. It is found that the direction of the transport along the potential is determined by the asymmetry of the potential and the position of the wheel. The average velocity is a peaked function of the angular speed (or the diffusion coefficient) and the position of the peak shifts to large angular speed(or diffusion coefficient) when the diffusion coefficient (or the angular speed) increases. There exists an optimal angular speed (or diffusion coefficient) at which the effective diffusion coefficient takes its maximal value. Remarkably, the giant acceleration of diffusion is observed by suitably adjusting the system parameters. The parameters corresponding to the maximum effective diffusion coefficient are not the same as the parameters at which average velocity is maximum.