Spontaneous Demixing of Binary Colloidal Flocks

TL;DR

This paper demonstrates that heterogeneity in active speeds and non-reciprocal interactions cause spontaneous demixing in binary colloidal flocks, revealing principles of self-organization in multi-component active systems.

Contribution

It introduces a combined experimental and theoretical framework showing how heterogeneity and non-reciprocal interactions lead to self-sorting in binary active fluids.

Findings

Heterogeneity induces spontaneous demixing in binary colloidal systems.

Non-reciprocal interactions contribute to self-sorting behavior.

General principles for organizing multi-component active matter are established.

Abstract

Population heterogeneity is ubiquitous among active living systems, but little is known about its role in determining their spatial organization and large-scale dynamics. Combining evidence from synthetic active fluids assembled from self-propelled colloidal particles along with theoretical predictions at the continuum scale, we demonstrate the spontaneous demixing of binary polar liquids within circular confinement. Our analysis reveals how both active speed heterogeneity and non-reciprocal repulsive interactions lead to self-sorting behavior. By establishing general principles for the self-organization of binary polar liquids, our findings highlight the specificity of multi-component active systems.