Low-valency scalable quantum error correction with a dynamic compass code

Quantum Physics [Submitted on 15 Apr 2026] Low-valency scalable quantum error correction with a dynamic compass code Jun Zen, Xanda C. Kolesnikow, Campbell K. McLauchlan, Georgia M. Nixon, Thomas R. Scruby, Seok-Hyung Lee, Stephen D. Bartlett, Benjamin J. Brown, Robin Harper The ongoing development of hardware that is capable of reliably executing general quantum algorithms requires quantum error-correcting codes that are both practical for realisation and rapidly reduce logical error rates as they are scaled up. Here we introduce the dynamic compass code, a code that can be implemented with a modest footprint on the heavy-hex lattice while also demonstrating a threshold. The dynamic code is obtained by choosing a novel measurement schedule for the syndrome extraction circuit of the heavy-hex subsystem code. We numerically evaluate its performance and observe that different choices of schedule can provide a trade-off in protection against logical errors in the X vs Z basis. We also demonstrate that this new measurement schedule provides the code with a threshold for stability experiments. We finally show how the dynamic compass code could be used for fault-tolerant logic by illustrating lattice surgery between code patches. Comments: 15 pages; 18 figures; comments welcome Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.14299 [quant-ph]   (or arXiv:2604.14299v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.14299 Focus to learn more Submission history From: Benjamin Brown [view email] [v1] Wed, 15 Apr 2026 18:00:23 UTC (10,794 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?)