Aumann's theorem beyond ontology: quantum, postquantum, and indefinite causal order
Summarize this article with:
Quantum Physics arXiv:2603.23595 (quant-ph) [Submitted on 24 Mar 2026] Title:Aumann's theorem beyond ontology: quantum, postquantum, and indefinite causal order Authors:Carlo Cepollaro, Andrea Di Biagio View a PDF of the paper titled Aumann's theorem beyond ontology: quantum, postquantum, and indefinite causal order, by Carlo Cepollaro and 1 other authors View PDF HTML (experimental) Abstract:Agreement theorems are no-go results about rational disagreement: if two agents start from a common prior and their posterior beliefs are common knowledge, they cannot assign different probabilities to the same event. Standard treatments of the result have the agents reason about an underlying state of the world, which has lead some to ask whether the result can extend to quantum or postquantum phenomena, where such a description may no longer be appropriate. We derive an operational version of Aumann's agreement theorem without assuming an objective state of the world and instead focusing only on what is observed. This allows us to establish the theorem's validity in quantum theory and even in situations with indefinite causal order or involving hypothetical postquantum phenomena. We comment on seemingly contradictory results in the literature and point to the one place where the theorem might fail: Wigner's friend-type situations. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2603.23595 [quant-ph] (or arXiv:2603.23595v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2603.23595 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Carlo Cepollaro [view email] [v1] Tue, 24 Mar 2026 18:00:00 UTC (89 KB) Full-text links: Access Paper: View a PDF of the paper titled Aumann's theorem beyond ontology: quantum, postquantum, and indefinite causal order, by Carlo Cepollaro and 1 other authorsView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-03 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?) Links to Code Toggle Papers with Code (What is Papers with Code?) 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?)