Fault-Tolerant Error Detection Above Break-Even for Multi-Qubit Gates

Quantum Physics [Submitted on 14 Apr 2026] Fault-Tolerant Error Detection Above Break-Even for Multi-Qubit Gates Colburn Riffel, Reece Robertson, Peter Hendrickson A fully fault-tolerant implementation of the quantum error-detecting Iceberg [[2m, 2m-2, 2]] code applied to a Toffoli circuit achieved beyond-break-even error detection on a leading trapped-ion quantum computer, where the effect of encoding a circuit with a quantum error-detection code enables increased fidelity compared to an unencoded circuit. This code was also applied to Bell state preparation circuits, where a lean non-fault-tolerant implementation of the Iceberg code enables a fidelity gain as well. This highlights the important point that, at least for small-scale circuits with a substantial portion of error-free runs, it can be effective simply to use error detection to filter out the runs with errors. Furthermore, experiments performed in this work highlight the necessity for judicious compilation of circuits not only for a given hardware but also within a quantum error detection code. Comments: Submitted on World Quantum Day, 14 April, 2026 Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.13219 [quant-ph]   (or arXiv:2604.13219v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.13219 Focus to learn more Submission history From: Reece Robertson [view email] [v1] Tue, 14 Apr 2026 18:43:55 UTC (318 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 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?)