Separation of interacting active particles in an asymmetric channel

TL;DR

This paper investigates how interacting active particles in an asymmetric channel can be separated based on their mass by tuning external forces and interactions, revealing optimal conditions for selective separation.

Contribution

It introduces a method to separate particles of different masses by analyzing their velocities under various interaction and force parameters, including empirical relations for optimal separation.

Findings

Particles of moderate mass have maximum velocity without interaction.

Interaction introduces an additional velocity peak at lower mass.

Tuning parameters allows selective separation of particles by mass.

Abstract

We study the diffusive behaviour of interacting active particles (self-propelled) with mass $m$ in an asymmetric channel. The particles are subjected to an external oscillatory force along the length of the channel. In this setup, particles may exhibit rectification. In the absence of interaction, the mean velocity $\langle v \rangle$ of the particles shows a maximum at moderate $m$ values. It means that particles of moderate $m$ have higher velocities than the others. However, by incorporating short-range interaction between the particles, $\langle v \rangle$ exhibits an additional peak at lower $m$ values, indicating that particles of lower and moderate m can be separated simultaneously from the rest. Furthermore, by tuning the interaction strength, the self-propelled velocity, and the parameters of the oscillatory force, one can selectively separate the particles of lower $m$, moderate $m$, or both. Empirical relations for estimating the optimal mass as a function of these parameters are discussed. These findings are beneficial for separating the particles of selective $m$ from the rest of the particles.