Glassy Ratchets for Collectively Interacting Particles

TL;DR

This paper demonstrates that ratchet effects can emerge in disordered, glassy media of interacting particles without a fixed substrate, driven by asymmetric ac forces, with simulations and a simple model revealing complex behaviors.

Contribution

It introduces the concept of ratchet effects in glassy, interacting particle systems without quenched disorder, supported by simulations and a theoretical model.

Findings

Ratchet effects occur in disordered interacting particle systems without a substrate.

Asymmetric ac drives induce net particle flux in such media.

Flux reversals depend on particle density and temperature.

Abstract

We show that ratchet effects can occur in a glassy media of interacting particles where there is no quenched substrate. We consider simulations of a disordered binary assembly of colloids in which only one species responds to a drive. We apply an asymmetric ac drive that would produce no net dc drift of an isolated overdamped particle. When interacting particles are present, the asymmetric ac drive produces a ratchet effect. A simple model captures many of the results from simulations, including flux reversals as a function of density and temperature.