Focusing by blocking: repeatedly generating central density peaks in self-propelled particle systems by exploiting diffusive processes

TL;DR

This paper shows how boundary conditions and controlled propulsion switching can repeatedly create and restore a central density peak in self-propelled particles, revealing a reversible aspect of their diffusive behavior.

Contribution

It introduces a method to generate and restore a non-stationary density peak in self-propelled particles using boundary conditions and propulsion control, highlighting partial reversibility.

Findings

Repeatedly generates central density peaks

Demonstrates reversibility of diffusive behavior

Proposes experimental verification

Abstract

Over the past few years the displacement statistics of self-propelled particles has been intensely studied, revealing their long-time diffusive behavior. Here, we demonstrate that a concerted combination of boundary conditions and switching on and off the self-propelling drive can generate and afterwards arbitrarily often restore a non-stationary centered peak in their spatial distribution. This corresponds to a partial reversibility of their statistical behavior, in opposition to the above-mentioned long-time diffusive nature. Interestingly, it is a diffusive process that mediates and makes possible this procedure. It should be straightforward to verify our predictions in a real experimental system.