Flexible integration of gigahertz nanomechanical resonators with a superconducting microwave resonator using a bonded flip-chip method

We demonstrate strong coupling of gigahertz-frequency nanomechanical resonators to a frequency-tunable superconducting microwave resonator via a galvanically bonded flip-chip method. By tuning the microwave resonator with an external magnetic field, we observe a series of hybridized microwave-mechanical modes and report coupling strengths of similar to 15 MHz at cryogenic temperatures. The demonstrated multi chip approach provides flexible rapid characterization and simplified fabrication and could potentially enable coupling between a variety of quantum systems. Our work represents a step toward a plug-and-play architecture for building more complex hybrid quantum systems.