Stochastic ratcheting of two dimensional colloids : Directed current and dynamical transitions

TL;DR

This study uses molecular dynamics simulations to explore how stochastic ratcheting influences directed current and phase transitions in two-dimensional colloids, revealing resonance effects and non-equilibrium re-entrant phase changes.

Contribution

It introduces a combined numerical and analytical approach to understand stochastic ratcheting effects on colloidal dynamics and phase behavior.

Findings

Resonance in directed current depends non-monotonically on density.

Non-equilibrium re-entrant transitions occur between solid and liquid phases.

Analytic results agree well with simulation data.

Abstract

We present results of molecular dynamics simulations for two-dimensional repulsively interacting colloids driven by a one dimensional asymmetric and commensurate ratchet potential, switching on and off stochastically. This drives a time-averaged directed current of colloids, exhibiting resonance with change in ratcheting frequency, where the resonance frequency itself depends non-monotonically on density. Using scaling arguments, we obtain analytic results that show good agreement with numerical simulations. With increasing ratcheting frequency, we find non-equilibrium re-entrant transitions between solid and modulated liquid phases.