Measuring the Internal Temperature of a Levitated Nanoparticle in High Vacuum

摘要

The interaction of an object with its surrounding bath can lead to a couplingbetween the object's internal degrees of freedom and its center-of-mass motion.This coupling is especially important for nanomechanical oscillators, which areamongst the most promising systems for preparing macroscopic objects in quantummechanical states. Here we exploit this coupling to derive the internaltemperature of a levitated nanoparticle from measurements of its center-of-massdynamics. For a laser-trapped silica particle in high vacuum we find aninternal temperature of $1000(60)\,\mathrm{K}$. The measurement and control ofthe internal temperature of nanomechanical oscillators is of fundamentalimportance because blackbody emission sets limits to the coherence ofmacroscopic quantum states.