Cosmic-ray and cosmic-ray-like events in a modular superconducting quantum processor

Quantum processors based on superconducting qubits have been scaling to larger systems, enabling for example the implementation of small-scale quantum error correction codes. However, ionizing radiation events, including those from cosmic rays, can introduce catastrophic chip-scale correlated errors that conventional error-correction codes, such as the surface code, cannot protect against. Here we explore the potential for a modular quantum computing architecture to survive such catastrophic events. We explore cosmic-ray and cosmic-ray-like events in a modular quantum processor composed of a motherboard and two flip-chip bonded daughterboards, and monitor the appearance of correlated qubit decay errors within a single module and across two physically separate modules. We report on the performance of this system, and comment on future prospects for such architectures in the presence of such errors.