Hyperuniform Active Chiral Fluids with Tunable Internal Structure

TL;DR

This paper demonstrates the experimental realization of a hyperuniform active fluid composed of chiral particles, revealing how chirality and activity influence hyperuniformity and clustering at different scales.

Contribution

It provides the first experimental evidence of hyperuniformity in a chiral active fluid with tunable internal structure, linking particle motion curvature to hyperuniformity loss.

Findings

Hyperuniformity coexists with large density fluctuations in the system.

Increasing motion curvature leads to loss of hyperuniformity and particle localization.

Chirality and activity interplay to determine the system's structural properties.

Abstract

Large density fluctuations observed in active systems and hyperuniformity are two seemingly incompatible phenomena. However, the formation of hyperuniform states has been recently predicted in non-equilibrium fluids formed by chiral particles performing circular motion with the same handedness. Here we report evidence of hyperuniformity realized in a chiral active fluid comprised of pear-shaped Quincke rollers of arbitrary handedness. We show that hyperuniformity and large density fluctuations, triggered by dynamic clustering, coexist in this system at different length scales. The system loses its hyperuniformity as the curvature of particles' motion increases transforming them into localized spinners. Our results experimentally demonstrate a novel hyperuniform active fluid and provide new insights into an interplay between chirality, activity and hyperuniformity.