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arXiv · 1808.04874

Quantum electromechanics of a hypersonic crystal

Mahmoud Kalaee·Mohammad Mirhosseini·Paul B. Dieterle·Matilda Peruzzo·Johannes M. Fink·Oskar Painter
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Abstract

Radiation pressure within engineered structures has recently been used to couple the motion of nanomechanical objects with high sensitivity to optical and microwave electromagnetic fields. Here, we demonstrate a form of electromechanical crystal for coupling microwave photons and hypersonic phonons by embedding the vacuum-gap capacitor of a superconducting resonator within a phononic crystal acoustic cavity. Utilizing a two-photon resonance condition for efficient microwave pumping and a phononic bandgap shield to eliminate acoustic radiation, we demonstrate large cooperative coupling ($C \approx 30$) between a pair of electrical resonances at $10$GHz and an acoustic resonance at $0.425$GHz. Electrical read-out of the phonon occupancy shows that the hypersonic acoustic mode has an intrinsic energy decay time of $2.3$ms and thermalizes close to its quantum ground-state of motion (occupancy $1.5$) at a fridge temperature of $10$mK. Such an electromechanical transducer is envisioned as part of a hybrid quantum circuit architecture, capable of interfacing to both superconducting qubits and optical photons.

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Mahmoud Kalaee, Mohammad Mirhosseini, Paul B. Dieterle, Matilda Peruzzo, Johannes M. Fink, Oskar Painter. 2018-08-14. Quantum electromechanics of a hypersonic crystal. https://doi.org/10.1038/s41565-019-0377-2

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