Mediating interactions between superconducting microwave cavities with three-wave mixing, part 2

Quantum memories formed from three-dimensional superconducting microwave cavities provide the coherence and large Hilbert spaces needed for quantum error correction. To date, coupling between these memories has been primarily facilitated by transmons. There, four-wave mixing allows for the creation of beam-splitter, single-mode, and two-mode-squeezing interactions, from which gates can be built. Although this approach has proven to be flexible and robust, the engineered couplings are accompanied by unwanted Kerr and Stark effects, which can limit the fidelity of cavity-cavity gates. Here, we design the nonlinear coupling element to be an RF-driven three-wave mixer. The desired bilinear interactions may then be engineered while suppressing spurious fourth-order processes. In this talk, we present preliminary measurements of two microwave cavities coupled by such a three-wave mixing element.