Mechanical Dissipation Below 1μHz with a Cryogenic Diamagnetic Levitated Micro-Oscillator

Ultralow-dissipation mechanical systems play an important role in metrology and exploring macroscopic quantum phenomena. Here we report a diamagnetic levitated micromechanical oscillator operating at 3 K with measured dissipation down to $0.59\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{Hz}$ and a quality factor up to $2\ifmmode\times\else\texttimes\fi{}{10}^{7}$. This mechanical system achieves the lowest dissipation among the state-of-the-art microscale and nanoscale mechanical systems reported to date, with orders-of-magnitude reduction over other systems based on different principles. The cryogenic diamagnetic levitated oscillator is applicable on a wide range of mass, making it a good candidate system for ultrasensitive measurements of both force and acceleration. By virtue of the strong magnetic gradient, this system is potentially capable of studying quantum spin mechanics.