Dispersionless motion in a driven periodic potential

TL;DR

This paper demonstrates that applying a zero-mean square-wave drive to particles in a periodic potential can induce and prolong dispersionless, coherent motion, surpassing the limitations of constant tilt methods.

Contribution

It introduces a novel driving protocol using square-wave external fields to achieve extended and controllable dispersionless motion in periodic potentials.

Findings

Coherent motion can be repeatedly induced with square-wave drives.

The duration of dispersionless motion can be significantly extended.

Coherent motion can be achieved at lower dispersion levels than with constant tilt.

Abstract

Recently, dispersionless (coherent) motion of (noninteracting) massive Brownian particles, at intermediate time scales, was reported in a sinusoidal potential with a constant tilt. The coherent motion persists for a finite length of time before the motion becomes diffusive. We show that such coherent motion can be obtained repeatedly by applying an external zero-mean square-wave drive of appropriate period and amplitude, instead of a constant tilt. Thus, the cumulative duration of coherent motion of particles is prolonged. Moreover, by taking an appropriate combination of periods of the external field, one can postpone the beginning of the coherent motion and can even have coherent motion at a lower value of position dispersion than in the constant tilt case.