Impact of inertia on biased Brownian transport in confined geometries

TL;DR

This paper investigates how inertia influences biased Brownian particles in confined channels, revealing that under certain conditions, equipartition breaks down, causing complex mobility behaviors and novel effects.

Contribution

It introduces an effective description of particle motion considering inertia and demonstrates the breakdown of equipartition in biased conditions through numerical simulations.

Findings

Mobility shows non-monotonic dependence on external force.

Equipartition can break down in the presence of bias.

Inertia significantly affects transport properties in confined geometries.

Abstract

We consider the impact of inertia on biased Brownian motion of point 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.