声子的量子跃迁：超导量子比特与纳米机械谐振器的量子非破坏测量

Takuma Makihara1†, Erik Szakiel1†, Matthew P. Maksymowych1, Oliver A. Hitchcock2, Kaveh Pezeshki1, Rachel G. Gruenke-Freudenstein1, Mihir Pendharkar1,2, Shannon P. Harvey3, David I. Schuster1,2, Amir H. Safavi-Naeini1* Quantum mechanics predicts that a vibrating object’s energy comes in discrete packets, yet no measurement of its position reveals this discreteness. resolving individual energy levels requires a qualitatively different measurement, one coupling to the resonator’s energy rather than its displacement. We use a superconducting qubit dispersively coupled to a nanomechanical resonator to perform repeated quantum nondemolition measurements of the phonon number. An aligned transfer-print technique integrating the qubit and resonator yields a mechanical lifetime of T1 = 2.1 milliseconds and a dispersive shift of 2χ∕2π = 328 kilohertz per phonon. …