CHIAGRAM · Chiral Active Granular Matter

Chiral Active Granular Matter

Active matter is ubiquitous in nature and encompasses a broad range of systems, from microscopic to macroscopic scales, that extract energy from their surroundings and convert it into directed motion. Examples include living microswimmers such as bacteria, spermatozoa, and cells, as well as collective groups of animals, from insects to birds. Most of these systems break rotational symmetry and, consequently, possess an intrinsic chirality, allowing one to distinguish between left- and right-handed active particles that move along clockwise or counterclockwise circular trajectories. The nonequilibrium dynamics of such chiral active systems have inspired the design of artificial microswimmers, such as active colloids, and macroscopic robots capable of efficiently exploring their environment or cooperating to move collectively in self-organized structures. The main goal of the CHIAGRAM project is to explore chirality in active granular matter, focusing on the dynamics of 3D-printed self-propelled robots, termed vibrobots. These vibrobots constitute a new class of self-propelled and self-rotating active materials that follow circular trajectories. Combining experiments and theory, the project investigates both single-particle and collective phenomena, their interactions with the environment, and the role of deformability - particularly in chain-like assemblies. CHIAGRAM opens a novel research direction at the interface between chirality and granular matter. This connection paves the way for systematic studies combining theoretical modeling and experimental realization of chiral granular systems. The rich experimental and theoretical results achieved within the project—ranging from single-particle properties to emergent collective behaviors—will inspire future investigations into the interplay between chirality and inertia. Furthermore, CHIAGRAM establishes an innovative framework to experimentally probe chirality in active matter and lays the groundwork for the design of active, deformable robotic materials whose properties can be tuned and optimized for self-organization and adaptive functionalities.

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