Thermal noise of a cryo-cooled silicon cantilever locally heated up to its melting point
arXiv:2101.09003 · doi:10.1103/PhysRevE.103.062125
Abstract
The Fluctuation-Dissipation Theorem (FDT) is a powerful tool to estimate the thermal noise of physical systems in equilibrium. In general however, thermal equilibrium is an approximation, or cannot be assumed at all. A more general formulation of the FDT is then needed to describe the behavior of the fluctuations. In our experiment we study a micro-cantilever brought out-ofequilibrium by a strong heat flux generated by the absorption of the light of a laser. While the base is kept at cryogenic temperatures, the tip is heated up to the melting point, thus creating the highest temperature difference the system can sustain. We independently estimate the temperature profile of the cantilever and its mechanical fluctuations, as well as its dissipation. We then demonstrate how the thermal fluctuations of all the observed degrees of freedom, though increasing with the heat flux, are much lower than what is expected from the average temperature of the system. We interpret these results thanks to a minimal extension of the FDT: this dearth of thermal noise arises from a dissipation shared between clamping losses and distributed damping.
References in corpus (5)
- Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA
- Resonance frequency shift of strongly heated micro-cantilevers
- Silicon cantilevers locally heated from 300K up to the melting point: temperature profile measurement from their resonances frequency shift
- Thermo-optical bistability in silicon micro-cantilevers
- Extended equipartition in a mechanical system subject to a heat flow: the case of localised dissipation