Quantum Flute: Multimode circuit QED with long-lived 3D cavities

Superconducting microwave cavities have been shown to have very long single-photon lifetimes, making them a valuable resource for quantum computation and simulation. One of the major sources of dissipation in such cavities is loss occurring at the seam between two parts of the cavity, which has resulted in the exploration of seamless designs\footnote{M. Reagor, et al., Phys. Rev. B 94, 014506 (2016).}. Here, we present a novel technique for fabricating seamless multimodal cavities, with a variety of mode distributions. We discuss measurements of the quality factors of the cavity modes, as well as schemes for quantum control of the modes using superconducting transmon qubits.