Strong Dispersive Coupling Between a Mechanical Resonator and a Fluxonium Superconducting Qubit
Nathan Lee, Yudan Guo, Agnetta Y. Cleland +10 more
We demonstrate strong dispersive coupling between a fluxonium superconducting qubit and a 690 megahertz mechanical oscillator, extending the reach of circuit quantum acousto-dynamics (cQAD) experiments into a new range of frequencies.We have engineered a qubit-phonon coupling rate of g ≈ 2π × 14 MHz, and achieved a dispersive interaction that exceeds the decoherence rates of both systems while the qubit and mechanics are highly nonresonant ( /g 10).Leveraging this strong coupling, we perform phonon-number-resolved measurements of the mechanical resonator and investigate its dissipation and dephasing properties.Our results demonstrate the potential for fluxonium-based hybrid quantum systems, and a path for developing new quantum sensing and information processing schemes with phonons at frequencies below 700 MHz to significantly expand the toolbox of cQAD.
arXiv:2304.13589•PRX Quantum•Dec 13, 2023•27 citations