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PLV: Plenarvorträge

PLV VII

PLV VII: Plenarvortrag

Mittwoch, 19. März 2025, 14:00–14:45, H2

Variance sum rule for dissipative systems — •Felix Ritort — Small Biosystems Lab, Condensed Matter Physics Department, University of Barcelona, C/ Marti i Franques, 1, 08028 Barcelona (Spain)

Nonequilibrium pervades nature, from the expanding universe to climate dynamics, living cells, and molecular machines. Key to nonequilibrium states is the entropy production rate σ at which energy is dissipated to the environment. Despite its importance, σ remains challenging to measure, especially in nanoscale systems with limited access to microscopic variables. I present a recently introduced variance sum rule for displacement and force variances that permits measuring σ by constraining energetics through modeling [1,2]. We apply it to measure the first heat map of human red blood cells in experiments with laser optical tweezers and ultrafast life-imaging microscopy. The variance sum rule sets a new resource for energy inference in nonequilibrium systems [3], from measuring entropy production in active and living matter to identifying hidden sources of energy and dissipation.

[1] Di Terlizzi, I., Gironella, M., Herráez-Aguilar, D., Betz, T., Monroy, F., Baiesi, M., & Ritort, F. (2024). Variance sum rule for entropy production. Science, 383(6686), 971-976. [2] Di Terlizzi, I., Baiesi, M., & Ritort, F. (2024). Variance sum rule: proofs and solvable models. New Journal of Physics, 26, 063013. [3] Roldán, É. (2024). Thermodynamic probes of life. Science, 383(6686), 952-953.

Keywords: Nonequilibrium physics; Entropy production; Thermodynamics of life; Single-cell experiments; Optical tweezers and microscopy