Particle diode: Rectification of interacting Brownian ratchets

TL;DR

This paper demonstrates that interacting Brownian particles can act as a diode, allowing directional transport depending on frequency, with optimal interaction strength and a velocity that decreases with system size.

Contribution

It introduces a particle diode mechanism based on interacting Brownian particles with frequency-dependent rectification and size-dependent velocity scaling.

Findings

Transport is prohibited from free to ac end at low frequencies.

Transport from ac to free end occurs at low frequencies.

Velocity scales as N^{-1} with system size.

Abstract

Transport of Brownian particles interacting with each other via the Morse potential is investigated in the presence of an ac driving force applied locally at one end of the chain. By using numerical simulations, we find that the system can behave as a particle diode for both overdamped and underdamped cases. For low frequencies, the transport from the free end to the ac acting end is prohibited, while the transport from the ac acting end to the free end is permitted. However, the polarity of the particle diode will reverse for medium frequencies. There exists an optimal value of the well depth of the interaction potential at which the average velocity takes its maximum. The average velocity $\upsilon$ decreases monotonically with the system size $N$ by a power law $\upsilon \propto N^{-1}$.