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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 31: Responsive and Adaptive Polymers
CPP 31.1: Invited Talk
Wednesday, March 19, 2025, 16:15–16:45, H38
Moving with minimum effort – Optimal work protocols for systems with memory — •Sarah Loos1, Samuel Monter2, Felix Ginot2, and Clemens Bechinger2 — 1DAMTP, University of Cambridge, UK — 2University of Konstanz
Energy optimization is crucial in engineering and may also govern nonequilibrium processes in chemical and biological systems. Finding optimal solutions for microscale processes–dominated by thermal or nonthermal fluctuations and often displaying memory effects arising from internal degrees of freedom or coupling to viscoelastic environments–posses additional challenges, necessitating general guiding principles. We demonstrate such a general principle for the fundamental problem of dragging a harmonic trap containing a single particle over a finite distance within a given time while minimizing work input. We show that the optimal dragging protocol and the corresponding mean particle trajectory both exhibit time-reversal symmetry, which is a universal and exclusive feature of the optimal solutions. The symmetry principle holds across all media described by a linear generalized Langevin equation, irrespective of the memory kernel or noise properties, including glassy, granular, and active media. For intrinsically driven systems, such as active particles, we show that the optimal protocols remain identical to those for passive systems, but work fluctuations are always increased [2]. [1] S.A.M. Loos, S. Monter, F. Ginot, and C. Bechinger, Phys. Rev. X 14, 021032 (2024). [2] R. Garcia-Millan, J. Schüttler, M.E. Cates, and S.A.M. Loos, ArXiv:2407.18542 (2024).
Keywords: Optimal Control; Non-Markovian processes; Generalized Langevin Equations; Non-equilibrium Soft Matter; Active matter