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 coupling between the object’s internal degrees of freedom and its center-of-mass motion. This coupling is especially important for nanomechanical oscillators, which are among the most promising systems for preparing macroscopic objects in quantum mechanical states. Here we exploit this coupling to derive the internal temperature of a levitated nanoparticle from measurements of its center-of-mass dynamics. For a laser-trapped silica particle in high vacuum, we find an internal temperature of 1000(60)K. The measurement and control of the internal temperature of nanomechanical oscillators is of fundamental importance because black-body emission sets limits to the coherence of macroscopic quantum states.