Measuring quasiparticle dynamics for particle impact reconstruction in a superconducting qubit chip

Quantum Physics [Submitted on 14 Apr 2026] Measuring quasiparticle dynamics for particle impact reconstruction in a superconducting qubit chip E. Celi, R. Linehan, P. M. Harrington, M. Li, H. D. Pinckney, K. Serniak, W. D. Oliver, J. A. Formaggio, E. Figueroa-Feliciano, D. Baxter Quasiparticle poisoning following particle impacts poses a significant challenge to the development of fault-tolerant superconducting quantum computers, as a sudden excess of quasiparticles can simultaneously degrade the coherence of multiple qubits across large device arrays. In this work, we present a statistical analysis that models the time evolution of radiation-induced qubit energy relaxation through quasiparticle density dynamics. This study provides insight into quasiparticle loss processes by distinguishing between recombination and trapping decay channels and assessing their respective impact on qubit performance. We precisely measure quasiparticle recombination in multiple transmon qubits and uncover an unexpected dependence of qubit relaxation dynamics on deposited energy. By linking correlated relaxation events across qubits to ballistic phonon propagation, we introduce a statistical localization approach to extract the energy deposited in the substrate, which is in good agreement with Monte Carlo simulation. This work establishes the quantitative framework for using an arbitrary subset of superconducting transmon qubits in a QPU as energy-resolving witness particle detectors. Comments: 15 pages, 16 figures Subjects: Quantum Physics (quant-ph); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det) Report number: FERMILAB-PUB-26-0146-ETD-PPD Cite as: arXiv:2604.13176 [quant-ph]   (or arXiv:2604.13176v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.13176 Focus to learn more Submission history From: Emanuela Celi [view email] [v1] Tue, 14 Apr 2026 18:00:39 UTC (5,291 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 Change to browse by: hep-ex physics physics.ins-det References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)