Superconducting qubit decoherence correlated with detected radiation events

TL;DR

This study demonstrates that cosmic radiation events can cause correlated decoherence in superconducting qubits, highlighting the need to consider such effects in quantum error correction.

Contribution

The paper introduces a platform that detects radiation-induced phonon bursts and correlates them with qubit decoherence, revealing the impact of cosmic rays on qubit coherence.

Findings

Radiation events cause up to 30.5% reduction in qubit $T_1$ and $T_2$.

Detection of muons correlates with immediate qubit decoherence.

Platform enables systematic study of radiation effects on qubits.

Abstract

Most quantum error correction (QEC) protocols for superconducting qubits assume spatially and temporally uncorrelated decoherence events; however, recent evidence suggests that cosmic radiation induces spatially correlated errors. We present a platform that sandwiches a superconducting transmon qubit between two microwave kinetic inductance detector (MKID) arrays, enabling real-time detection of radiation-induced phonon bursts. By synchronizing MKID event detection with single-shot measurements of qubit energy relaxation ($T_1$) and phase coherence ($T_2$), we observe statistically significant reductions in both $T_1$ and $T_2$-up to 30.5%-immediately following dual MKID events attributed to penetrating muons. Our findings directly link radiating events to correlated qubit decoherence. Furthermore, our experimental platform provides a foundation for systematic studies of radiation effects, the development of shielding and mitigation techniques, and the refinement of error-correction algorithms tailored to correlated noise sources.