Dresden 2026 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
BP: Fachverband Biologische Physik
BP 34: Focus Session: Emergent Transport in Active Systems (joint session DY/BP)
BP 34.6: Talk
Thursday, March 12, 2026, 17:15–17:30, ZEU/0160
Directed motion of active collectives in activity gradients — •Hossein Vahid1, Jens-Uwe Sommer1,2, and Abhinav Sharma1,3 — 1Leibniz-Institut für Polymerforschung Dresden, 01069 Dresden, Germany — 2Technische Universität Dresden, 01069 Dresden, Germany — 3Institute of Physics, University of Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
Directed motion appears across all scales of active matter, from biomolecular condensates inside cells to large assemblies of migrating filaments. By simulating active particles and polymers, we identified the mechanisms that enable activity gradients to steer these collectives and control their assembly [1,2]. In cohesive mixtures, droplets climb activity gradients, fragment when the activity becomes too intense, and reassemble in low activity regions. This creates a robust cycle of positioning without needing any biochemical feedback. Similarly, in assemblies of active polar polymers, spatial gradients in activity, combined with temporally stochastic propulsion, generate net body forces on dimers, asters, and multiarm structures. This biases their motion toward high-activity regions and stabilizes long-lived entangled clusters even at low concentrations.
[1] H. Vahid, J.-U. Sommer, A. Sharma, Self-Organization and Cyclic Positioning of Active Condensates, arXiv preprint arXiv:2510.15771 (2025). [2] H. Vahid, J.-U. Sommer, A. Sharma, Collective dynamics in active polar polymer assemblies, Phys. Rev. Res. 7, L042031 (2025).
Keywords: Active Brownian particle; polar polymers; cohesive interactions; activity gradient