Emerging activity in bilayered dispersions with wake-mediated interactions

TL;DR

This paper investigates how wake-mediated interactions in bilayered particle systems lead to nonreciprocal forces, resulting in self-propelled clusters, enhanced diffusion, and novel melting behaviors, supported by simulations and theory.

Contribution

It demonstrates that nonreciprocal wake interactions induce activity and complex phase behaviors in bilayered dispersions, a novel insight into active matter systems.

Findings

Self-propelled clusters emerge when nonreciprocity exceeds a threshold.

Enhanced diffusivity observed in dense fluids due to activity.

Unusual melting scenarios are promoted by wake-mediated interactions.

Abstract

In a bilayered system of particles with wake-mediated interactions, the action-reaction symmetry for the effective forces between particles of different layers is broken. Under quite general conditions we show that, if the interaction nonreciprocity exceeds a certain threshold, this creates an active dispersion of self-propelled clusters of Brownian particles. The emerging activity promotes unusual melting scenarios and an enormous diffusivity in the dense fluid. Our results are obtained by computer simulation and analytical theory, and can be verified in experiments with colloidal dispersions and complex plasmas.