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DY: Fachverband Dynamik und Statistische Physik

DY 23: Stochastic Thermodynamics

DY 23.10: Talk

Wednesday, March 20, 2024, 12:00–12:15, BH-N 128

Thermodynamics of active matter: Tracking dissipation across scales — •Robin Bebon, Joshua F. Robinson, and Thomas Speck — Institute for Theoretical Physics 4, University of Stuttgart, Heisenbergstraße 3, 70569 Stuttgart, Germany

The non-equilibrium “active” nature of living systems becomes manifest in the spatial and temporal organization of hierarchical structures, which provide essential functionality. Maintaining activity is necessarily coupled to continual energy consumption, which in turn posits dissipation as the central constraint of any such process. Here we derive exact expressions for the dissipation rate of catalytically propelled active particles, ranging across length scales from individual agents to large-scale collectives. Commencing from a microscopic model of a single catalytic particle that interacts with explicit solute molecules, we motivate a mesoscopic many-body description reminiscent of active Brownian particles. Through further coarse-graining, we obtain a macroscopic field theoretic description based on effective hydrodynamic equations and sketch how to treat scalar field theories. This systematic bottom-up construction enables precise bookkeeping of the degrees of freedom that partake in the stochastic energetics and shows that dissipation is, both locally and globally, accompanied by a continual solute flux between solute reservoirs. We employ our results to gain insights into the thermodynamic footprint of confinement and the role of dissipation in motility-induced phase separation. Moreover, we demonstrate how the phenomenological framework of linear irreversible thermodynamics unfolds from our microscopic approach.

Keywords: active matter; stochastic thermodynamics; coarse-graining; dissipation; hydrodynamic equations