Mechanical systems operating in the quantum regime offer an attractive platform for quantum information processing, precision sensing, and probing fundamental physics. In this talk, I will present new techniques for generating and characterizing non-classical states of mechanical motion using superconducting qubits. Our approach couples the electrical and mechanical degrees of freedom via modulation of the electrostatic force in a miniaturized vacuum-gap capacitor. By eliminating the need for piezoelectricity, we are able to build and measure mechanical oscillators made of single-crystal silicon, a material with very low acoustic loss. Using the qubit as a probe of the oscillator’s coherence, we measure single-phonon decay and (echo) decoherence times of 25 ms and 1 ms, respectively. Moreover, we observes signatures of strong coupling between the mechanical oscillator and individual two-level-state defects, which are believed to be the microscopic origins of mechanical decoherence. These results opens up exciting opportunities to explore the fundamental limits of mechanical coherence and to employ mechanical oscillators as bosonic memory elements in quantum processors.
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