Rectification of self-propelled particles by symmetric barriers

TL;DR

This paper demonstrates that self-propelled particles can exhibit a net drift in symmetric periodic potentials through phase-shifted modulation of propulsion velocity, expanding understanding of rectification mechanisms beyond asymmetric barriers.

Contribution

It reveals that symmetric barriers can induce directed motion in self-propelled particles via phase-shifted propulsion modulation, providing analytical insights in the adiabatic limit.

Findings

Non-zero average drift occurs with symmetric barriers and phase-shifted propulsion.

Temperature influences the magnitude of the drift.

Asymmetric barriers can enhance or reverse the drift.

Abstract

The motion of self-propelled particles can be rectified by asymmetric or ratchet-like periodic patterns in space. Here we show that a non-zero average drift can already be induced in a periodic potential with symmetric barriers when the self-propulsion velocity is also symmetric and periodically modulated but phase-shifted against the potential. In the adiabatic limit of slow rotational diffusion we determine the mean drift analytically and discuss the influence of temperature. In the presence of asymmetric barriers modulating the self-propulsion can largely enhance the mean drift or even reverse it.