Dresden 2026 – scientific programme
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BP: Fachverband Biologische Physik
BP 28: Active Matter V (joint session DY/BP)
BP 28.4: Talk
Thursday, March 12, 2026, 10:30–10:45, ZEU/0160
Topology of pulsating active matter: Defect asymmetry controls emergent motility — •Luca Casagrande1, Alessandro Manacorda2, and Étienne Fodor1 — 1Department of Physics and Materials Science, University of Luxembourg, Luxembourg City, Luxembourg — 2CNR Institute of Complex Systems, Uos Sapienza, Rome, Italy
When heartbeats become irregular, spiral waves and motile defects emerge at the surface of cardiac tissues [1]. Capturing the emergence of defect motility despite the absence of any cellular flows is a theoretical challenge which has recently been tackled by models of actively deforming particles [2-4]. The interplay between individual pulsation of particles sizes, synchronization, and repulsion yields deformation waves resembling those of cardiac tissues. Combining particle-based and hydrodynamic approaches, we examine the statistics of defects in the collective deformation of particles. We rationalize defect motility as stemming from the breakdown of time-reversal and spatial symmetries, and provide predictions for the deformation profile near the defect core to quantify motility. [1] A. Karma, Annu. Rev. Condens. Matter Phys., 4, 313-337 (2013) [2] Y. Zhang, É. Fodor, Phys. Rev. Lett., 131, 238302 (2023) [3] A. Manacorda, É. Fodor, Phys. Rev. E, 111, L053401 (2025) [4] W. Piñeros, É. Fodor, Phys. Rev. Lett., 134, 038301 (2025)
Keywords: topological defects; contraction waves; phase transitions; active matter; hydrodynamics