Spatiotemporally Correlated Errors in Fluxonium Qubits

Spatiotemporally correlated errors, often caused by excess quasiparticles generated from ionizing radiation, present a significant challenge to scaling superconducting quantum processors. In this study, we investigate these errors in fluxonium qubits, which are a qubit circuit of interest due to their long coherence times and demonstrations of high-fidelity control. We examine the sensitivity of the fluxonium to correlated error bursts as a function of applied external flux, which is indicative of the relative contributions from quasiparticle tunneling at the single Josephson junction and the junction array superinductor. Our data informs ongoing efforts to improve the coherence of superconducting qubits and in particular informs mitigation strategies for spatiotemporally correlated errors in fluxonium.