Towards verified quantum speedup in a bosonic superconducting processor

We are developing a superconducting platform for boson sampling, aiming to demonstrate quantum speedup in a verifiable manner. Achieving this goal requires the deterministic preparation of nonclassical states in bosonic modes with high local dimensionality, the realization of high-fidelity beam-splitting interactions with all-to-all connectivity, and the ability to perform both homodyne/heterodyne detection and photon-counting measurements with high efficiency. In this presentation, I will discuss our experimental progress in developing these critical building blocks. Specifically, I will highlight results on fast state preparation achieved through combined charge and flux drives, as well as a novel protocol for homodyne and heterodyne detection on stationary bosonic modes, enabled by an ancillary qubit. Finally, I will outline our strategy for implementing quantum verification on this platform and achieving verified quantum speedup.