Radiation Bursts Reveal Limits of Gap Engineering

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Electron-Ion Collider

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A promising technique for mitigating radiation-induced errors in quantum chips wasn't as effective as expected

July 20, 2026

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High-energy impacts generate phonons that create quasiparticles, which increase qubit relaxation by tunneling across the junction.

Scientific Achievement

C2QA researchers at Yale found that superconducting gap engineering reduces radiation-induced quasiparticle bursts in transmon qubits by only 5x, rather than the expected 10,000x. The team identified slow phonon escape from the substrate as a key limiting factor.

Significance and Impact

Ionizing radiation creates correlated errors across multiple qubits, threatening large-scale quantum error correction. This work identifies larger superconducting gap differences and improved substrate thermalization as practical strategies for protecting future quantum processors.

Research Details

Substrate heats to ~90 mK during radiation bursts
Substrate stays hot for ~6 msec, 10x longer than the quasiparticle recombination time

Collaborating Institutions

Yale University

Publication

Nho, H., Connolly, T., Kurilovich, P. D., Diamond, S., Bøttcher, C. G. L., Glazman, L. I., and Devoret, M. H.
Recovery Dynamics of a Gap-Engineered Transmon after a Quasiparticle Burst
Physical Review Letters 136, 050601 (2026).
DOI: 10.1103/ql6q-wfpn

Acknowledgements

This research was sponsored by the Army Research Office (ARO) under Grants No. W911NF-22-1-0053 and No. W911NF-23-1-0051; by DARPA under Grant No. HR0011-24-2-0346; and by the U.S. Department of Energy (DOE), Office of Science, National Quantum Information Science Research Centers, Co-design Center for Quantum Advantage (C2QA), under Contract No. DE-SC0012704. Fabrication facilities were supported by the Yale Institute for Nanoscience and Quantum Engineering (YINQE) and the Yale University Cleanroom.

2026-23067 | INT/EXT | Newsroom

About C2QA

The U.S. Department of Energy Office of Science has established five National Quantum Information Science (QIS) Research Centers. These centers will accelerate the transformational advances in basic science and quantum-based technologies needed to assure continued U.S. leadership in QIS, consistent with the National Quantum Initiative Act. Led by Brookhaven National Laboratory, the Co-design Center for Quantum Advantage is building the fundamental tools necessary to create scalable, distributed, and fault-tolerant quantum computer systems.