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 $∼ 15 MHz$ 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.