Field-mediated active dynamical bonds

TL;DR

This paper demonstrates how shared field-mediated interactions enable active matter systems to achieve both structural stability and dynamic motion, overcoming traditional trade-offs.

Contribution

It introduces a novel approach using field-mediated bonds in active matter, allowing continuous tuning between stable structures and dynamic behaviors.

Findings

Droplet assemblies can self-stabilize via wavefield interference.

Different droplet sizes lead to distinct symmetry and packing behaviors.

Assemblies exhibit spontaneous rotation and controlled migration.

Abstract

Active matter systems typically exhibit a trade-off between structural robustness and dynamical freedom, limiting independent control over structure and motion. Here, we show that encoding interactions in a shared field overcomes this constraint, enabling continuous tuning between stable architectures and dynamically active states. Using droplets on a vibrated fluid bath as a minimal realization, we demonstrate that individually unstable units can collectively self-stabilize through field-mediated dynamical bonds. Arising from wavefield interference, these bonds form persistent, self-healing connections that preserve architecture while sustaining motion. Droplet size sets the symmetry of the interactions, with identical droplets forming rigid $\sigma$-like frameworks that enforce triangular packing, while smaller droplets enable $\pi$-like coordination that supports higher-order symmetries. The resulting assemblies exhibit both stability and sustained collective dynamics, including spontaneous rotation and controlled migration. This work establishes a general route to programmable active matter in which shared fields reconcile structural robustness with dynamical freedom.