Ultra-high quality factor of a levitated nanomechanical oscillator

A levitated nanomechanical oscillator under ultra-high vacuum (UHV) is highly isolated from its environment. It has been predicted that this isolation leads to very low mechanical dissipation rates. However, a gap persists between predictions and experimental data. Here, we levitate a silica nanoparticle in a linear Paul trap at room temperature, at pressures as low as $7\times {10}^{-11}$ mbar. We measure a dissipation rate of $2\pi \times 69(22)$ nHz, corresponding to a quality factor exceeding ${10}^{10}$, more than two orders of magnitude higher than previously shown. A study of the pressure dependence of the particle’s damping and heating rates provides insight into the relevant dissipation mechanisms.