TV-PROGRAMM

From collective motion to selective actuation | Olivier Dauchot , 45m 56s

Topic: Active matter and driven systems
Speaker: Dr. Olivier Dauchot, ESPCI Paris, 10 rue Vauquelin Paris, France

Polar active matter is made of a large number of out of equilibrium interacting units, which convert some source of energy into directed motion. Active liquids have been an intense topic of research in the past 25 years. There are however a number of cases, such as living or artificially powered structured materials, cohesive cell layers or simply very dense assemblies of self propelled particles, for which elasticity also matters and new questions arise.
For instance, how does crystallization take place in a dense liquid of active particles? In liquids alignment between the particles leads to collective motion. Are such large-scale motions frozen by crystallization, or does the crystal flow? Also, together with elasticity comes the concept of vibrational modes? How is distributed the energy harvested by the active particles amongst those modes?
In this talk, I will present experimental and theoretical works addressing these question in various settings. More specifically, I will discuss how self-propelled particles, which take their momentum from a substrate, generically couple their orientational dynamics to their translational one. In the liquid phase this coupling is responsible for an effective mutual alignment and collective motion. When elasticity is present, it leads to an elasto-active feedback responsible for the condensation of the dynamics on a pair of modes that are non trivially selected. I will discuss how one can understand the emergence of different types of such collective actuation and how they compare to dynamics observed in bacterial colonies and epithelial tissues.

Livestream der Plenar-Vorträge der 12. Liquid Matter Conference in Mainz vom 22. - 27. September 2024

Wanderschaft im Handwerk - traditionell und progressiv , 16m 38s

Die Wanderschaft oder Walz im Handwerk ist eine jahrhundertealte Tradition - nach der Lehrzeit ziehen noch immer viele Handwerksgesellen (und -gesellinnen) für mehrere Jahre los, um in verschiedenen Bereichen praktisch zu arbeiten und um Land und Leute kennenzulernen. So auch Gunni und Wiki, die in dieser Doku von ihren Erfahrungen, Motivationen und ihrem Selbstverständnis als WandergesellInnen berichten.

Autor und Schnitt: Florian Metz
Kamera und Ton: Aurelius Lopp, Lena Heutmann