Catégorie : preprint

Aubin Archambault, Caroline Crauste-Thibierge, Alberto Imparato, Christopher Jarzynski, Sergio Ciliberto and Ludovic Bellon, submitted to Phy. Rev. Lett.

arXiv: 2407.17414

We investigate the thermodynamic properties of an information engine that extracts work from thermal fluctuations, using a mechanical cantilever submitted to electrostatic feedback control. The cantilever’s position is continuously measured, and feedback is triggered by the first passage of the system across a fixed threshold. The information ∆I associated with the feedback is based on the first-passage-time distribution. In this setting, we derive and experimentally verify two distinct fluctuation theorems that involve ∆I and give a tight bound on the work produced by the engine. Our results extend beyond the specific application to our experiment: we develop a general framework for obtaining fluctuation theorems and work bounds, formulated in terms of probability distributions of protocols rather than underlying measurement outcomes.

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Clément Chardin, Sébastien Pairis, Sabine Douillet, Moïra Hocevar, Julien Claudon, Jean-Philippe Poizat, Ludovic Bellon and Pierre Verlot, submitted to Nano Letters

arXiv: 2407.20740

We report a new scanning thermomechanical microscopy platform enabling to both heat and acquire the fluctuations of mechanical nanostructures with nanometric resolution. We use this platform to image the nanomechanical noise response of a 40 nm diameter nanowire while scanning a localized heat source across its surface. We develop a thermal backaction model, which we use to demonstrate a close connection between the structure of the nanowire, its thermal response, its dissipation and its fluctuations. We notably identify the presence of a localized thermoelastic defect, which we demonstrate behaves as a single fluctuation hub, whose e-beam excitation yields a far off-equilibrium vibrational state, largely dominated by the quantum fluctuations of the heating source. Our platform is of interest for future development of ultra-low loss nanophononic devices, and appears as a new playground for investigating quantum thermodynamics in the strongly dissipative regime and at room temperature.

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