Non-classical energy squeezing of a macroscopic mechanical oscillator

Optomechanics and electromechanics have made it possible to prepare macroscopic mechanical oscillators in their quantum ground states, quadrature squeezed entangled states of motion. In addition coaxing ever larger more tangible objects into a regime behavior, this new capability has encouraged ideas using the processing communication information as precision force sensors operating beyond standard limit. But effectively linear interaction between motion light or electricity precludes access broader class motion, such cat energy states. Indeed, early optomechanical proposals noted possibility escape restriction by creating strong quadratic coupling light. Although there been experimental demonstrations quadratically coupled systems, these not yet accessed nonclassical Here we create levels Cooper-pair box (CPB) qubit. By monitoring qubit's transition frequency, detect oscillator's phonon distribution rather than its position. Through microwave frequency drives that change both state oscillator qubit, then dissipatively stabilize with large mean number 43 sub-Poissonian fluctuations approximately 3. observe striking feature coupling: recoil caused qubit transitions, closely analogous vibronic transitions molecules.