Beating three-parameter precision trade-offs with entangling collective measurements
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Quantum Physics arXiv:2604.08871 (quant-ph) [Submitted on 10 Apr 2026] Title:Beating three-parameter precision trade-offs with entangling collective measurements Authors:Simon K. Yung, Wen-Zhe Yan, Lan-Tian Feng, Aritra Das, Jiayi Qin, Guang-Can Guo, Ping Koy Lam, Jie Zhao, Zhibo Hou, Lorcan O. Conlon, Syed M. Assad, Xi-Feng Ren, Guo-Yong Xiang View a PDF of the paper titled Beating three-parameter precision trade-offs with entangling collective measurements, by Simon K. Yung and 12 other authors View PDF HTML (experimental) Abstract:Quantum-mechanical incompatibility, which precludes the simultaneous precise measurement of non-commuting observables, imposes fundamental limits on the rate at which classical information can be extracted. While the potential to surpass these limits using entangling collective measurements has been explored for two parameters, the regime of three or more parameters remains largely unexplored despite its fundamental and technological importance. Here, we investigate the three-parameter trade-off relations for estimating the Bloch vector components of a qubit, comparing conventional individual measurements with entangling collective measurements. We theoretically derive and experimentally implement optimal collective measurements on two identically prepared qubits using a programmable photonic circuit. Our experimental results demonstrate a clear violation of the entanglement-free trade-off relation -- by an average of 16 standard deviations -- achieving a tomography precision beyond the reach of any individual measurement scheme. This work directly confirms that optimal collective measurements can surpass the fundamental quantum limits of individual schemes in a three-parameter setting -- thereby deepening our understanding of quantum uncertainty relations beyond the two-parameter regime and providing a clear strategy to overcome the precision trade-offs imposed by quantum incompatibility. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.08871 [quant-ph] (or arXiv:2604.08871v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2604.08871 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Simon K Yung [view email] [v1] Fri, 10 Apr 2026 02:21:53 UTC (4,129 KB) Full-text links: Access Paper: View a PDF of the paper titled Beating three-parameter precision trade-offs with entangling collective measurements, by Simon K. Yung and 12 other authorsView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADSGoogle Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... Data provided by: 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 Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv (What is alphaXiv?) Links to Code Toggle CatalyzeX Code Finder for Papers (What is CatalyzeX?) DagsHub Toggle DagsHub (What is DagsHub?) GotitPub Toggle Gotit.pub (What is GotitPub?) Huggingface Toggle Hugging Face (What is Huggingface?) ScienceCast Toggle ScienceCast (What is ScienceCast?) Demos Demos Replicate Toggle Replicate (What is Replicate?) Spaces Toggle Hugging Face Spaces (What is Spaces?) Spaces Toggle TXYZ.AI (What is TXYZ.AI?) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower (What are Influence Flowers?) Core recommender toggle CORE Recommender (What is CORE?) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs. Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)