Microscopic origin of tunable assembly forces in chiral active environments

TL;DR

This paper investigates how chiral active particles generate tunable, long-range assembly forces between passive objects, revealing the microscopic origins and conditions for stable assembly in nonequilibrium active environments.

Contribution

It uncovers the microscopic mechanisms by which chiral active matter induces stable assembly forces, contrasting with achiral active baths where assembly does not occur.

Findings

Chiral active particles produce stable assembly forces.

Oscillatory force profiles are explained by active Brownian motion.

Chiral motion leads to fluxes consistent with an odd diffusion tensor.

Abstract

The fluctuations of a nonequilibrium bath enable dynamics inaccessible to any equilibrium system. Exploiting the driven dynamics of active matter in order to do useful work has become a topic of significant experimental and theoretical interest. Due to the unique modalities controlling self-assembly, the interplay between passive solutes and the particles in an active bath has been studied as a potential driving force to guide assembly of otherwise non-interacting objects. Here, we investigate and characterize the microscopic origins of the attractive and repulsive interactions between passive solutes in an active bath. We show that, while assembly does not occur dynamically for achiral active baths, chiral active particles can produce stable and robust assembly forces. We both explain the observed oscillatory force profile for active Brownian particles and demonstrate that chiral active motion leads to fluxes consistent with an odd diffusion tensor that, when appropriately tuned, produces long-ranged assembly forces.