Stationary entanglement of a levitated oscillator with an optical field

Stationary entanglement between the motion of macroscopic objects and light is a long-standing goal of quantum optomechanics, with implications for both fundamental tests of quantum physics and emerging quantum technologies. We report the generation of quantum entanglement between the center-of-mass motion of a nanosphere levitated in an optical tweezer inside an optical cavity and the electromagnetic field. Using heterodyne detection, we reconstructed the full set of optomechanical correlations and observed a violation of separability bounds between the mechanical motion and a propagating optical mode, demonstrating the distribution of nonclassical correlations beyond the interaction region. The entanglement was generated at room temperature and remained robust over a broad range of parameters. Our results establish levitated optomechanical systems as a platform for continuous-variable quantum communication and for tests of macroscopic quantum physics.