Modular Superconducting Quantum Processors with High-Fidelity Links

We address the scalability of quantum processors by connecting multiple computing units through high-fidelity links, proposing a hierarchical interconnection strategy. At meter scales, we connect non-local processors housed in separate cryostats via the exchange of microwave-frequency radiation [1]. On shorter distances, we capitalize on three-dimensionally integrated devices with reliable parameter targeting thanks to a polymer spacer process [2]. We extend this demonstrated technology to multi-chip modules that alleviate finite yield and correlated errors across a device. We demonstrate a high-fidelity inter-module two-qubit gate between qubits located on separate dies, bonded to a common carrier chip. We discuss first applications in quantum algorithms distributed across modules.