Dresden 2026 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 21: Stochastic Thermodynamics

DY 21.8: Vortrag

Dienstag, 10. März 2026, 11:45–12:00, ZEU/0114

Optimal Localisation against a Flow — •Till Welker and Patrick Pietzonka — School of Physics and Astronomy, University of Edinburgh, United Kingdom

How much work does it cost for a propelled particle to stay localised near a stationary target, defying thermal noise and a constant flow that would carry it away? We study the control of such a particle in finite time and find optimal protocols for time-dependent propulsion speed and diffusivity, without feedback. Accuracy, quantified via the mean squared deviation from the target, and energetic cost turn out to be connected by a trade-off relation, which complements the one between precision and cost known in stochastic thermodynamics. We show that accuracy better than a certain threshold requires active driving , which comes at a cost that increases with accuracy. The optimal protocols have discontinuous propulsion speed and diffusivity, switching between a passive drift state with vanishing diffusivity and an active propulsion state. If the initial position is fixed, an initial jump of the particle, enabled by a sudden burst of propulsion, can be optimal. This study highlights how a time-dependent diffusivity enhances optimal control and sets benchmarks for artificial self-propelled particles navigating noisy environments.

Keywords: Stochastic Thermodynamics; Optimal Control; Localisation; Navigation