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Ilya Golokolenov presents

 Nanomechanics-based thermodynamics: from molecules to mesoscopic phonons

Wesnesday,  December 21st 2022 at 14:00

Room Louis Weil E424 – Building E – CNRS

Link visio: https://smartvisio.neel.cnrs.fr/b/edd-ord-zmu-kui

The defence will be in English.



Nano-Electro-Mechanical Systems (NEMS) are unique sensing devices, with record breaking sensitivity in force/mass detection. They can also be thought of as model systems for physicists, implementing given concepts into engineered, artifical devices. To do so, they can be interfaced with the most sensitive detection scheme: optomechanics, which has already been demonstrated in the microwave domain, in cryogenic conditions.
In this Thesis, we probe concepts linked to thermodynamics at small scales. In the first place, we investigate the optomechanics platform with one optical and one mechanical  degree of freedom. Classical back-action concepts are studied with an artificial bath. Using a quantum-limited detection scheme, we demonstrated our ability to measure classical thermal fluctuations for a single phononic mode. In the second place, we use nanomechanical resonators as sensors for low temperature investigations: namely here, we probed the specific properties of a rarefied ideal gas. We demonstrate that we can resolve the signature of the boundary (Knudsen) layer of the gas onto the probe element itself.