Quantum sensing and cooling in three-dimensional levitated cavity optomechanics

Abstract

Typical quantum cavity optomechanics allows cooling and detection of a single mechanical degree of freedom with its motion along the cavity axis. However, a recent breakthrough using cavities populated solely by coherent scattering (CS) allowing quantum ground-state cooling of levitated nanoparticles [U. Delić, Science 367, 892 (2020)SCIEAS0036-807510.1126/science.aba3993], is uniquely three dimensional (3D) in character, with coupling along all three spatial axes. We present a reanalysis of current experiments and show that the underlying behavior is far from the addition of independent one dimensional spectral components and that cooling and sensing analysis must consider, to date neglected, nontrivial 3D hybridization effects arising from interferences between the x,y,z modes as well as the optical modes. These lead to new heating and sympathetic cooling channels and modify phonon occupancies. Unique to these systems, we find a close relation between cavity-mediated and direct hybridization terms that can completely suppress the 3D behavior.