Generating non-classical states of engineered macroscopic mechanical elements.

Previous results:  Fabricated a superconducting resonator that couples to mechanical elements on chip. We use microwave signals to coherently control the mechanical elements at the quantum level. (1) Coupling a superconducting qubit to a mechanical element. A first step in generating non-classical states of a single mechanical element. (2) Coupling a mechanical element to a 3 dimensional bulk microwave cavity (Peterson et. al., “Ultrastrong Parametric Coupling between a Superconducting Cavity and a Mechanical Resonator”, PRL 123, 247701 (2019)). Reaching the ultra-strong coupling regime for the first time. (3) Building and measuring a novel architecture of two separate mechanical modes for full coherent control of mechanics. Generation of mechanical entanglement between two macroscopic mechanical objects. The chip made enables state preparation, coherent control of the two drums and simultaneous readout of the state of the two mechanical modes. It serves as a milestone on the path to a fully programmable multi-element mechanical processor. See Kotler et. al., “Tomography of Entangled Macroscopic Mechanical Objects”, Science 372, 622-625 (2021).