Séminaire

Mardi 25 Novembre 2025 à 11h00.

Spatiotemporal Control of Active Granular Matter via Illumination

Sara LEVAY
(Université de Navarre)

Salle de Séminaires Lippmann

Invité(e) par
Osvanny RAMOS

présentera en 1 heure :

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Active matter systems—ensembles of self-propelled, interacting agents—display collective behaviors that often transcend the properties of individual units. These systems span scales and disciplines, from physics and biology to robotics and medicine. In our work, we investigate an active granular system composed of macroscopic agents that interact exclusively through contact and whose activity can be finely tuned via illumination [1].
Our experimental platform consists of hexbug-based robotic particles equipped with photovoltaic cells, and a fully programmable illumination panel provides complete external spatiotemporal control of their activity. In this seminar, I will first present the clustering behavior of the system under homogeneous illumination, demonstrating a transition between unstable and stable clusters, characterized experimentally and captured by a simple kinetic model. I will then explore how more complex illumination patterns direct particle motion, examining whether clustering enhances or impedes effective transport in these macroscopic photoactive systems.

[1] S. Lévay et al, Cluster Dynamics in Macroscopic Photoactive Particles, Phys. Rev. Lett.135, 098301 (2025).

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