Micromachined Integrated Quantum Circuit Containing a Superconducting Qubit

The next step in building quantum computers is to develop hardware architectures that allow scalability without sacrificing coherence. Future designs seem headed toward multilayered circuits with embedded three-dimensional structures and superconducting coatings. The authors demonstrate a multilayered integrated quantum circuit, combining a micromachined microwave cavity resonator with a superconducting qubit. They address the mechanism of coupling and its control, engineering considerations that affect coherence times, and challenges in fabrication such as superconductor bonding.