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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 39: Focus Session: Physics of Fluctuating Paths (joint session DY/CPP)
CPP 39.6: Talk
Wednesday, March 29, 2023, 16:15–16:30, ZEU 160
Entropons as vibrational excitations in active solids — •Lorenzo Caprini1, Umberto Marini Bettolo Marconi2, Andrea Puglisi3, and Hartmut Löwen1 — 1Heinrich-Heine-Universität Düsseldorf — 2Scuola di Scienze e Tecnologie, University of Camerino — 3Istituto dei Sistemi Complessi, CNR
We study the vibrational properties of non-equilibrium active crystals, i.e. solids formed by active particles, that are intrinsically out of equilibrium and governed by entropy production. As known in solid-state physics, equilibrium crystals are characterized by basic collective excitations with thermal origins that are named phonons. In this talk, I will show that active crystals are described by additional vibrational excitations that we called `entropons' because each of them represents a mode of spectral entropy production. Entropons coexist with phonons and dominate over them for large activity, i.e. when the solid is far from equilibrium, while they vanish in equilibrium conditions. Their existence can be verified in experiments on dense self-propelled colloidal Janus particles and granular active matter, as well as in living systems such as dense cell monolayers.