2024/10/17 by Yating Zheng, Tang, Weizhen, Zheng, Yating +10
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Astro and Planetary Science #FOS: Physical sciences #Micro and Nano Robotics #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2410.13705
openalex publication_date 2024/10/17 · openalex created_date 2024/10/21 · openalex updated_date 2026/07/28
We study the emerging collective states in a simple mechanical model of a dense group of self-propelled polar disks with off-centered rotation, confined within a circular arena. Each disk presents self-alignment towards the sum of contact forces acting on it, resulting from disk-substrate interactions, while also displaying mutual alignment with neighbors due to having its center of rotation located a distance R behind its centroid so that central contact forces can also introduce torques. The effect of both alignment mechanisms produces a variety of collective states that combine high-frequency localized circular oscillations with low-frequency milling around the center of the arena, in fluid or solid regimes. We consider cases with small/large R values, isotropic/anisotropic disk-substrate damping, smooth/rough arena boundaries, different densities, and multiple systems sizes, showing that the emergent collective states that we identify are robust, generic, and potentially observable in real-world natural or artificial systems.