Transient rectification of Brownian diffusion with asymmetric initial distribution

TL;DR

This paper investigates how a transient average velocity can develop in Brownian particles due to nonlinear effects, even when starting from zero initial velocity, highlighting implications for complex systems in viscous media.

Contribution

It introduces a nonlinear correction to dissipative forces causing temporary velocity in Brownian particles with potential relevance to dissociation processes.

Findings

Finite systematic velocity can develop transiently

Nonlinear correction couples velocity to higher moments

Effect relevant in viscous medium dissociation

Abstract

In an ensemble of non-interacting Brownian particles, a finite systematic average velocity may temporarily develop, even if it is zero initially. The effect originates from a small nonlinear correction to the dissipative force, causing the equation for the first moment of velocity to couple to moments of higher order. The effect may be relevant when a complex system dissociates in a viscous medium with conservation of momentum.