{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:01:16Z","timestamp":1782864076987,"version":"3.54.5"},"reference-count":107,"publisher":"Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften","license":[{"start":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T00:00:00Z","timestamp":1779753600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"United Kingdom Engineering and Physical Sciences Research Council (EPSRC), DTP Studentship","award":["EP\/W524657\/1"],"award-info":[{"award-number":["EP\/W524657\/1"]}]},{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","award":["CEECINST\/00062\/2018"],"award-info":[{"award-number":["CEECINST\/00062\/2018"]}]}],"content-domain":{"domain":["quantum-journal.org"],"crossmark-restriction":false},"short-container-title":["Quantum"],"abstract":"<jats:p>The Frauchiger\u2013Renner paradox derives an inconsistency when quantum theory is used to describe the use of itself, by means of a scenario where agents model other agents quantumly and reason about each other&amp;apos;s knowledge. We observe that logical contextuality (\u00e0 la Hardy) is the key ingredient of the FR paradox, and we provide a stronger paradox based on the strongly contextual GHZ\u2013Mermin scenario. In contrast to the FR paradox, this GHZ\u2013FR paradox neither requires post-selection nor any reasoning by observers who are modelled quantumly. If one accepts the universality of quantum theory including superobservers, we propose a natural extension of Peres&amp;apos;s dictum to resolve these extended Wigner&amp;apos;s friend paradoxes.<\/jats:p>","DOI":"10.22331\/q-2026-05-26-2116","type":"journal-article","created":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T07:38:37Z","timestamp":1779781117000},"page":"2116","update-policy":"https:\/\/doi.org\/10.22331\/q-crossmark-policy-page","source":"Crossref","is-referenced-by-count":1,"title":["A refined Frauchiger\u2013Renner paradox based on strong contextuality"],"prefix":"10.22331","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4459-1191","authenticated-orcid":false,"given":"Laurens","family":"Walleghem","sequence":"first","affiliation":[{"name":"Department of Mathematics, University of York, York, United Kingdom"},{"name":"INL \u2013 International Iberian Nanotechnology Laboratory, Braga, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0465-8518","authenticated-orcid":false,"given":"Rui Soares","family":"Barbosa","sequence":"additional","affiliation":[{"name":"INL \u2013 International Iberian Nanotechnology Laboratory, Braga, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6189-7144","authenticated-orcid":false,"given":"Matthew F.","family":"Pusey","sequence":"additional","affiliation":[{"name":"Department of Mathematics, University of York, York, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6647-3252","authenticated-orcid":false,"given":"Stefan","family":"Weigert","sequence":"additional","affiliation":[{"name":"Department of Mathematics, University of York, York, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"9598","published-online":{"date-parts":[[2026,5,26]]},"reference":[{"key":"0","doi-asserted-by":"publisher","unstructured":"D. Frauchiger and R. Renner, Quantum theory cannot consistently describe the use of itself, Nat. Commun. 9, 3711 (2018).","DOI":"10.1038\/s41467-018-05739-8"},{"key":"1","doi-asserted-by":"publisher","unstructured":"E. P. Wigner, Remarks on the mind-body question, in The Scientist Speculates, edited by I. J. Good (Basic Books, New York, 1961) Chap. 13, pp. 284\u2013302.","DOI":"10.1007\/978-3-642-78374-6_20"},{"key":"2","unstructured":"V. Baumann, A. Hansen, and S. Wolf, The measurement problem is the measurement problem is the measurement problem (2016), arXiv:1611.01111 [quant-ph]."},{"key":"3","unstructured":"V. Vilasini and M. P. Woods, A general framework for consistent logical reasoning in Wigner&apos;s friend scenarios: subjective perspectives of agents within a single quantum circuit (2022), arXiv:2209.09281 [quant-ph]."},{"key":"4","doi-asserted-by":"publisher","unstructured":"R. Kastner, Unitary-only quantum theory cannot consistently describe the use of itself: On the Frauchiger\u2013Renner paradox, Found. Phys. 50, 441\u2013456 (2020).","DOI":"10.1007\/s10701-020-00336-6"},{"key":"5","doi-asserted-by":"publisher","unstructured":"V. Vilasini, N. Nurgalieva, and L. del Rio, Multi-agent paradoxes beyond quantum theory, New J. Phys. 21, 113028 (2019).","DOI":"10.1088\/1367-2630\/ab4fc4"},{"key":"6","doi-asserted-by":"publisher","unstructured":"\u010c. Brukner, A no-go theorem for observer-independent facts, Entropy 20, 350 (2018).","DOI":"10.3390\/e20050350"},{"key":"7","unstructured":"C. L. Jones and M. P. Mueller, On the significance of Wigner&apos;s friend in contexts beyond quantum foundations (2025), arXiv:2402.08727 [quant-ph]."},{"key":"8","unstructured":"L. Walleghem, Stunned by sleeping beauty: How prince probability updates his forecast upon their fateful encounter (2024), arXiv:2408.06797 [math.PR]."},{"key":"9","doi-asserted-by":"publisher","unstructured":"L. Hardy, Nonlocality for two particles without inequalities for almost all entangled states, Phys. Rev. Lett. 71, 1665 (1993).","DOI":"10.1103\/PhysRevLett.71.1665"},{"key":"10","unstructured":"S. Aaronson, It&apos;s hard to think when someone Hadamards your brain (2018), blog post."},{"key":"11","unstructured":"A. Drezet, About Wigner Friend&apos;s and Hardy&apos;s paradox in a Bohmian approach: a comment of `Quantum theory cannot consistently describe the use of itself&apos; (2018), arXiv:1810.10917 [quant-ph]."},{"key":"12","unstructured":"S. B. Montanhano, Contextuality in multi-agent paradoxes (2023), arXiv:2305.07792 [quant-ph]."},{"key":"13","unstructured":"S. Fortin and O. Lombardi, Wigner and his many friends: A new no-go result? (2019), arXiv:1904.07412 [quant-ph]."},{"key":"14","unstructured":"J. Bub, In defense of a \"single-world\" interpretation of quantum mechanics (2018), arXiv:1804.03267 [quant-ph]."},{"key":"15","doi-asserted-by":"publisher","unstructured":"H. Dourdent, A G\u00f6delian hunch from quantum theory, in Undecidability, Uncomputability, and Unpredictability (Springer International Publishing, 2021) p. 97\u2013113.","DOI":"10.1007\/978-3-030-70354-7_7"},{"key":"16","doi-asserted-by":"publisher","unstructured":"N. D. Mermin, Simple unified form for the major no-hidden-variables theorems, Phys. Rev. Lett. 65, 3373 (1990a).","DOI":"10.1103\/PhysRevLett.65.3373"},{"key":"17","doi-asserted-by":"publisher","unstructured":"D. M. Greenberger, M. A. Horne, and A. Zeilinger, Going beyond Bell&apos;s theorem, in Bell&apos;s theorem, quantum theory, and conceptions of the universe, Fundamental Theories of Physics, Vol. 37, edited by M. Kafatos (Kluwer, Dordrecht, 1989) pp. 69\u201372.","DOI":"10.1007\/978-94-017-0849-4_10"},{"key":"18","doi-asserted-by":"publisher","unstructured":"K.-W. Bong, A. Utreras-Alarc\u00f3n, F. Ghafari, Y.-C. Liang, N. Tischler, E. G. Cavalcanti, G. J. Pryde, and H. M. Wiseman, A strong no-go theorem on the Wigner&apos;s friend paradox, Nat. Phys. 16, 1199\u20131205 (2020).","DOI":"10.1038\/s41567-020-0990-x"},{"key":"19","doi-asserted-by":"publisher","unstructured":"E. G. Cavalcanti and H. M. Wiseman, Implications of Local Friendliness violation for quantum causality, Entropy 23, 925 (2021).","DOI":"10.3390\/e23080925"},{"key":"20","doi-asserted-by":"publisher","unstructured":"M. Haddara and E. G. Cavalcanti, A possibilistic no-go theorem on the Wigner\u2019s friend paradox, New J. Phys. 25, 093028 (2023).","DOI":"10.1088\/1367-2630\/aceea3"},{"key":"21","doi-asserted-by":"publisher","unstructured":"G. Leegwater, When Greenberger, Horne and Zeilinger meet Wigner&apos;s friend, Found. Phys. 52, 68 (2022).","DOI":"10.1007\/s10701-022-00586-6"},{"key":"22","doi-asserted-by":"publisher","unstructured":"D. Schmid, Y. Y\u012bng, and M. Leifer, A review and analysis of six extended Wigner&apos;s friend arguments (2023), arXiv:2308.16220 [quant-ph].","DOI":"10.48550\/arXiv.2308.16220"},{"key":"23","unstructured":"N. Ormrod and J. Barrett, A no-go theorem for absolute observed events without inequalities or modal logic (2022), arXiv:2209.03940 [quant-ph]."},{"key":"24","unstructured":"N. Ormrod, V. Vilasini, and J. Barrett, Which theories have a measurement problem? (2023), arXiv:2303.03353 [quant-ph]."},{"key":"25","doi-asserted-by":"crossref","unstructured":"N. Nurgalieva and L. del Rio, Inadequacy of modal logic in quantum settings (2018), arXiv:1804.01106 [quant-ph].","DOI":"10.4204\/EPTCS.287.16"},{"key":"26","doi-asserted-by":"publisher","unstructured":"M. \u017bukowski and M. Markiewicz, Physics and metaphysics of Wigner&apos;s friends: Even performed premeasurements have no results, Phys. Rev. Lett. 126, 130402 (2021).","DOI":"10.1103\/PhysRevLett.126.130402"},{"key":"27","doi-asserted-by":"publisher","unstructured":"L. Walleghem, R. Wagner, D. Schmid, and Y. Y\u012bng, Extended Wigner&apos;s friend paradoxes do not require nonlocal correlations, Phys. Rev. A 112, 022212 (2025a).","DOI":"10.1103\/n4hv-rlgj"},{"key":"28","doi-asserted-by":"publisher","unstructured":"L. Walleghem, Y. Y\u012bng, R. Wagner, and D. Schmid, Connecting extended Wigner\u2019s friend arguments and noncontextuality, Quantum 9, 1819 (2025b).","DOI":"10.22331\/q-2025-07-31-1819"},{"key":"29","unstructured":"S. Gao, Quantum theory is incompatible with relativity: A new proof beyond Bell&apos;s theorem and a test of unitary quantum theories (2019), preprint."},{"key":"30","doi-asserted-by":"publisher","unstructured":"P. A. Gu\u00e9rin, V. Baumann, F. Del Santo, and \u010c. Brukner, A no-go theorem for the persistent reality of Wigner&apos;s friend&apos;s perception, Commun. Phys. 4, 93 (2021).","DOI":"10.1038\/s42005-021-00589-1"},{"key":"31","doi-asserted-by":"publisher","unstructured":"Y. Y\u012bng, M. M. Ansanelli, A. D. Biagio, E. Wolfe, and E. G. Cavalcanti, Relating Wigner&apos;s friend scenarios to nonclassical causal compatibility, monogamy relations, and fine tuning, Quantum 8, 1485 (2024).","DOI":"10.22331\/q-2024-09-26-1485"},{"key":"32","unstructured":"A. Rela\u00f1o, Decoherence allows quantum theory to describe the use of itself (2018), arXiv:1810.07065 [quant-ph]."},{"key":"33","doi-asserted-by":"publisher","unstructured":"A. Rela\u00f1o, Decoherence framework for Wigner&apos;s-friend experiments, Phys. Rev. A 101, 032107 (2020).","DOI":"10.1103\/PhysRevA.101.032107"},{"key":"34","doi-asserted-by":"publisher","unstructured":"R. Gambini, L. P. Garc\u00eda-Pintos, and J. Pullin, Single-world consistent interpretation of quantum mechanics from fundamental time and length uncertainties, Phys. Rev. A 100, 012113 (2019).","DOI":"10.1103\/PhysRevA.100.012113"},{"key":"35","doi-asserted-by":"publisher","unstructured":"D. Lazarovici and M. Hubert, How Quantum Mechanics can consistently describe the use of itself, Sci. Rep. 9, 470 (2019).","DOI":"10.1038\/s41598-018-37535-1"},{"key":"36","doi-asserted-by":"publisher","unstructured":"A. Sudbery, Single-world theory of the extended Wigner&apos;s friend experiment, Found. Phys. 47, 658\u2013669 (2017).","DOI":"10.1007\/s10701-017-0082-7"},{"key":"37","doi-asserted-by":"publisher","unstructured":"D. Deutsch, Quantum theory, the Church\u2013Turing principle and the universal quantum computer, Proc. R. Soc. Lond. A 400, 97\u2013117 (1985).","DOI":"10.1098\/rspa.1985.0070"},{"key":"38","doi-asserted-by":"publisher","unstructured":"N. Nurgalieva and R. Renner, Testing quantum theory with thought experiments, Contemporary Physics 61, 193\u2013216 (2020).","DOI":"10.1080\/00107514.2021.1880075"},{"key":"39","doi-asserted-by":"publisher","unstructured":"\u010c. Brukner, On the quantum measurement problem, Quantum [Un] Speakables II: Half a Century of Bell&apos;s Theorem , 95\u2013117 (2017).","DOI":"10.48550\/arXiv.1507.05255"},{"key":"40","doi-asserted-by":"crossref","unstructured":"A. Utreras-Alarc\u00f3n, E. G. Cavalcanti, and H. M. Wiseman, Allowing Wigner&apos;s friend to sequentially measure incompatible observables (2023), arXiv:2305.09102 [quant-ph].","DOI":"10.1098\/rspa.2024.0040"},{"key":"41","unstructured":"J. Szangolies, The quantum Rashomon effect: A strengthened Frauchiger-Renner argument (2020), arXiv:2011.12716 [quant-ph]."},{"key":"42","unstructured":"\u010c. Brukner, Qubits are not observers\u2013a no-go theorem (2021), arXiv:2107.03513 [quant-ph]."},{"key":"43","doi-asserted-by":"publisher","unstructured":"J. Allam and A. Matzkin, From observer-dependent facts to frame-dependent measurement records in Wigner friend scenarios, Europhys. Lett. 143, 60001 (2023).","DOI":"10.1209\/0295-5075\/acfbf4"},{"key":"44","doi-asserted-by":"publisher","unstructured":"A. Di Biagio, P. Don\u00e0, and C. Rovelli, The arrow of time in operational formulations of quantum theory, Quantum 5, 520 (2021).","DOI":"10.22331\/q-2021-08-09-520"},{"key":"45","unstructured":"N. Ormrod and J. Barrett, Quantum influences and event relativity (2024), arXiv:2401.18005 [quant-ph]."},{"key":"46","doi-asserted-by":"publisher","unstructured":"A. Baltag and S. Smets, Logic meets Wigner\u2019s Friend (and their Friends), Int. J. Theor. Phys. 63, 97 (2024).","DOI":"10.1007\/s10773-024-05611-0"},{"key":"47","doi-asserted-by":"publisher","unstructured":"R. Healey, Quantum theory and the limits of objectivity, Found. Phys. 48, 1568\u20131589 (2018).","DOI":"10.1007\/s10701-018-0216-6"},{"key":"48","doi-asserted-by":"publisher","unstructured":"S. Abramsky and A. Brandenburger, The sheaf-theoretic structure of non-locality and contextuality, New J. Phys. 13, 113036 (2011).","DOI":"10.1088\/1367-2630\/13\/11\/113036"},{"key":"49","doi-asserted-by":"publisher","unstructured":"S. Abramsky, R. S. Barbosa, K. Kishida, R. Lal, and S. Mansfield, Contextuality, Cohomology and Paradox, in 24th EACSL Annual Conference on Computer Science Logic (CSL 2015), Leibniz International Proceedings in Informatics (LIPIcs), Vol. 41, edited by S. Kreutzer (Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik, Dagstuhl, Germany, 2015) pp. 211\u2013228.","DOI":"10.4230\/LIPIcs.CSL.2015.211"},{"key":"50","unstructured":"R. S. Barbosa, Contextuality in quantum mechanics and beyond, DPhil thesis, University of Oxford (2015)."},{"key":"51","doi-asserted-by":"publisher","unstructured":"S. Abramsky, R. S. Barbosa, and S. Mansfield, Contextual fraction as a measure of contextuality, Phys. Rev. Lett. 119, 050504 (2017).","DOI":"10.1103\/PhysRevLett.119.050504"},{"key":"52","doi-asserted-by":"publisher","unstructured":"N. D. Mermin, Quantum mysteries revisited, Am. J. Phys. 58, 731\u2013734 (1990b).","DOI":"10.1119\/1.16503"},{"key":"53","doi-asserted-by":"publisher","unstructured":"S. Abramsky and B. Coecke, Categorical quantum mechanics, Handbook of quantum logic and quantum structures 2, 261\u2013325 (2009).","DOI":"10.48550\/arXiv.0808.1023"},{"key":"54","doi-asserted-by":"publisher","unstructured":"B. Coecke and A. Kissinger, Picturing Quantum Processes: A First Course in Quantum Theory and Diagrammatic Reasoning (Cambridge University Press, 2017).","DOI":"10.1017\/9781316219317"},{"key":"55","doi-asserted-by":"publisher","unstructured":"O. Oreshkov, F. Costa, and \u010c. Brukner, Quantum correlations with no causal order, Nat. Commun. 3, 1092 (2012).","DOI":"10.1038\/ncomms2076"},{"key":"56","doi-asserted-by":"publisher","unstructured":"Y.-C. Liang, R. W. Spekkens, and H. M. Wiseman, Specker\u2019s parable of the overprotective seer: A road to contextuality, nonlocality and complementarity, Phys. Rep. 506, 1\u201339 (2011).","DOI":"10.1016\/j.physrep.2011.05.001"},{"key":"57","unstructured":"A. Sudbery, The hidden assumptions of Frauchiger and Renner (2019), arXiv:1905.13248 [quant-ph]."},{"key":"58","unstructured":"R. Fagin, J. Y. Halpern, Y. Moses, and M. Vardi, Reasoning about knowledge (MIT press, 2004)."},{"key":"59","doi-asserted-by":"publisher","unstructured":"P. Blackburn, M. De Rijke, and Y. Venema, Modal logic: graph. Darst, Vol. 53 (Cambridge University Press, 2001).","DOI":"10.1017\/CBO9781107050884"},{"key":"60","doi-asserted-by":"publisher","unstructured":"J. B. DeBrota, C. A. Fuchs, and R. Schack, Respecting one\u2019s fellow: QBism\u2019s analysis of Wigner\u2019s friend, Found. Phys. 50, 1859\u20131874 (2020).","DOI":"10.1007\/s10701-020-00369-x"},{"key":"61","doi-asserted-by":"publisher","unstructured":"A. Peres, Unperformed experiments have no results, Am. J. Phys. 46, 745\u2013747 (1978).","DOI":"10.1119\/1.11393"},{"key":"62","unstructured":"D. V. Tausk, A brief introduction to the foundations of quantum theory and an analysis of the Frauchiger-Renner paradox (2018), arXiv:1812.11140 [quant-ph]."},{"key":"63","doi-asserted-by":"publisher","unstructured":"J. Bub, Understanding the Frauchiger\u2013Renner argument, Found. Phys. 51, 36 (2021).","DOI":"10.1007\/s10701-021-00420-5"},{"key":"64","doi-asserted-by":"publisher","unstructured":"R. Muci\u00f1o and E. Okon, Wigner&apos;s convoluted friends, Stud. Hist. Philos. Sci. B 72, 87\u201390 (2020).","DOI":"10.1016\/j.shpsb.2020.07.001"},{"key":"65","doi-asserted-by":"publisher","unstructured":"F. J. Boge, Quantum information versus epistemic logic: An analysis of the Frauchiger\u2013Renner theorem, Found. Phys. 49, 1143\u20131165 (2019).","DOI":"10.1007\/s10701-019-00298-4"},{"key":"66","doi-asserted-by":"publisher","unstructured":"P. Fraser, N. Nurgalieva, and L. Rio, Fitch&apos;s knowability axioms are incompatible with quantum theory, J. Philos. Logic 52 (2023).","DOI":"10.1007\/s10992-023-09717-4"},{"key":"67","doi-asserted-by":"publisher","unstructured":"A. Corti, V. Fano, and G. Tarozzi, A Logico-Epistemic Investigation of Frauchiger and Renner\u2019s paradox, Int. J. Theor. Phys. 62, 54 (2023).","DOI":"10.1007\/s10773-023-05313-z"},{"key":"68","unstructured":"M. Ara\u00fajo, The flaw in Frauchiger and Renner&apos;s argument (2018)."},{"key":"69","doi-asserted-by":"publisher","unstructured":"L. Del Rio and R. Renner, Reply to: Quantum mechanical rules for observed observers and the consistency of quantum theory, Nat. Commun. 15, 3024 (2024).","DOI":"10.1038\/s41467-024-47172-0"},{"key":"70","doi-asserted-by":"publisher","unstructured":"A. Di Biagio and C. Rovelli, Stable facts, relative facts, Found. Phys. 51, 1\u201313 (2021).","DOI":"10.1007\/s10701-021-00429-w"},{"key":"71","doi-asserted-by":"publisher","unstructured":"E. G. Cavalcanti, A. Di Biagio, and C. Rovelli, On the consistency of relative facts (2023), arXiv:2305.07343 [quant-ph].","DOI":"10.1007\/s13194-023-00551-8"},{"key":"72","doi-asserted-by":"publisher","unstructured":"M. Losada, R. Laura, and O. Lombardi, Frauchiger-Renner argument and quantum histories, Phys. Rev. A 100, 052114 (2019).","DOI":"10.1103\/PhysRevA.100.052114"},{"key":"73","doi-asserted-by":"publisher","unstructured":"M. Schlosshauer, Quantum decoherence, Phys. Rep. 831, 1\u201357 (2019).","DOI":"10.1016\/j.physrep.2019.10.001"},{"key":"74","doi-asserted-by":"publisher","unstructured":"M. Schlosshauer, Decoherence, the measurement problem, and interpretations of quantum mechanics, Rev. Mod. Phys. 76, 1267\u20131305 (2005).","DOI":"10.1103\/RevModPhys.76.1267"},{"key":"75","doi-asserted-by":"publisher","unstructured":"M. Schlosshauer, Decoherence: the Quantum-to-Classical Transition (Springer, Berlin and Heidelberg, 2007).","DOI":"10.1007\/978-3-540-35775-9"},{"key":"76","doi-asserted-by":"publisher","unstructured":"G. C. Ghirardi, A. Rimini, and T. Weber, A model for a unified quantum description of macroscopic and microscopic systems, in Quantum Probability and Applications II: Proceedings of a Workshop held in Heidelberg, West Germany, October 1\u20135, 1984 (Springer, 1985) pp. 223\u2013232.","DOI":"10.1007\/BFb0074474"},{"key":"77","doi-asserted-by":"publisher","unstructured":"G. C. Ghirardi, A. Rimini, and T. Weber, Unified dynamics for microscopic and macroscopic systems, Phys. Rev. D 34, 470\u2013491 (1986).","DOI":"10.1103\/PhysRevD.34.470"},{"key":"78","doi-asserted-by":"publisher","unstructured":"R. Penrose, On gravity&apos;s role in quantum state reduction, Gen. Relativ. Gravit. 28, 581\u2013600 (1996).","DOI":"10.1007\/BF02105068"},{"key":"79","doi-asserted-by":"publisher","unstructured":"L. Diosi, A universal master equation for the gravitational violation of quantum mechanics, Phys. Lett. A 120, 377\u2013381 (1987).","DOI":"10.1016\/0375-9601(87)90681-5"},{"key":"80","doi-asserted-by":"publisher","unstructured":"A. Bassi and G. Ghirardi, Dynamical reduction models, Phys. Rep. volume 379, 257\u2013426 (2003).","DOI":"10.1016\/S0370-1573(03)00103-0"},{"key":"81","doi-asserted-by":"publisher","unstructured":"S. Forstner, M. Zych, S. Basiri-Esfahani, K. E. Khosla, and W. P. Bowen, Nanomechanical test of quantum linearity, Optica 7, 1427\u20131434 (2020).","DOI":"10.1364\/OPTICA.391671"},{"key":"82","doi-asserted-by":"publisher","unstructured":"I. Arnquist, F. Avignone III, A. Barabash, C. Barton, K. Bhimani, E. Blalock, B. Bos, M. Busch, M. Buuck, T. Caldwell, et al., Search for spontaneous radiation from wave function collapse in the majorana demonstrator, Phys. Rev. Lett. 129, 080401 (2022).","DOI":"10.1103\/PhysRevLett.129.080401"},{"key":"83","doi-asserted-by":"publisher","unstructured":"S. Donadi, K. Piscicchia, R. Del Grande, C. Curceanu, M. Laubenstein, and A. Bassi, Novel CSL bounds from the noise-induced radiation emission from atoms, Eur. Phys. J. C 81, 1\u201310 (2021).","DOI":"10.1140\/epjc\/s10052-021-09556-0"},{"key":"84","doi-asserted-by":"publisher","unstructured":"M. Carlesso, S. Donadi, L. Ferialdi, M. Paternostro, H. Ulbricht, and A. Bassi, Present status and future challenges of non-interferometric tests of collapse models, Nat. Phys. 18, 243\u2013250 (2022).","DOI":"10.1038\/s41567-021-01489-5"},{"key":"85","unstructured":"J. M. Renes, Consistency in the description of quantum measurement: Quantum theory can consistently describe the use of itself (2021), arXiv:2107.02193 [quant-ph]."},{"key":"86","unstructured":"V. Narasimhachar, Agents governed by quantum mechanics can use it intersubjectively and consistently (2020), arXiv:2010.01167 [quant-ph]."},{"key":"87","doi-asserted-by":"publisher","unstructured":"A. P. Polychronakos, Quantum mechanical rules for observed observers and the consistency of quantum theory, Nat. Commun. 15, 3023 (2024).","DOI":"10.1038\/s41467-024-47170-2"},{"key":"88","doi-asserted-by":"publisher","unstructured":"C. Rovelli, Relational quantum mechanics, Int. J. Theor. Phys. 35, 1637\u20131678 (1996).","DOI":"10.1007\/BF02302261"},{"key":"89","doi-asserted-by":"publisher","unstructured":"C. Rovelli, Space is blue and birds fly through it, Philos. Trans. R. Soc. A 376, 20170312 (2018).","DOI":"10.1098\/rsta.2017.0312"},{"key":"90","doi-asserted-by":"publisher","unstructured":"J. Lawrence, M. Markiewicz, and M. \u017bukowski, Relative facts of relational quantum mechanics are incompatible with quantum mechanics, Quantum 7, 1015 (2023).","DOI":"10.22331\/q-2023-05-23-1015"},{"key":"91","doi-asserted-by":"crossref","unstructured":"E. Adlam and C. Rovelli, Information is physical: Cross-perspective links in relational quantum mechanics (2022), arXiv:2203.13342 [quant-ph].","DOI":"10.31389\/pop.8"},{"key":"92","doi-asserted-by":"publisher","unstructured":"N. Harrigan and R. W. Spekkens, Einstein, incompleteness, and the epistemic view of quantum states, Found. Phys. 40, 125\u2013157 (2010).","DOI":"10.1007\/s10701-009-9347-0"},{"key":"93","doi-asserted-by":"publisher","unstructured":"M. F. Pusey, J. Barrett, and T. Rudolph, On the reality of the quantum state, Nat. Phys. 8, 475\u2013478 (2012).","DOI":"10.1038\/nphys2309"},{"key":"94","doi-asserted-by":"publisher","unstructured":"L. Hardy, Are quantum states real?, Int. J. Mod. Phys. B 27, 1345012 (2013).","DOI":"10.1142\/S0217979213450124"},{"key":"95","doi-asserted-by":"publisher","unstructured":"M. S. Leifer, Is the quantum state real? An extended review of $\\psi$-ontology theorems, quanta 3, 67\u2013155 (2014).","DOI":"10.12743\/quanta.v3i1.22"},{"key":"96","doi-asserted-by":"publisher","unstructured":"E. G. Cavalcanti, The view from a Wigner bubble, Found. Phys. 51, 39 (2021).","DOI":"10.1007\/s10701-021-00417-0"},{"key":"97","doi-asserted-by":"publisher","unstructured":"P. Martin-Dussaud, T. Carette, J. G\u0142owacki, V. Zatloukal, and F. Zalamea, Fact-nets: towards a mathematical framework for relational quantum mechanics, Found. Phys. 53, 26 (2023).","DOI":"10.1007\/s10701-022-00653-y"},{"key":"98","doi-asserted-by":"publisher","unstructured":"A.-C. de la Hamette and T. D. Galley, Quantum reference frames for general symmetry groups, Quantum 4, 367 (2020).","DOI":"10.22331\/q-2020-11-30-367"},{"key":"99","doi-asserted-by":"publisher","unstructured":"E. Schr\u00f6dinger, Discussion of probability relations between separated systems, in Mathematical Proceedings of the Cambridge Philosophical Society, Vol. 31 (Cambridge University Press, 1935) pp. 555\u2013563.","DOI":"10.1017\/S0305004100013554"},{"key":"100","doi-asserted-by":"publisher","unstructured":"H. M. Wiseman, S. J. Jones, and A. C. Doherty, Steering, entanglement, nonlocality, and the Einstein-Podolsky-Rosen paradox, Phys. Rev. Lett. 98, 140402 (2007).","DOI":"10.1103\/PhysRevLett.98.140402"},{"key":"101","doi-asserted-by":"publisher","unstructured":"O. G\u00fchne, E. Haapasalo, T. Kraft, J.-P. Pellonp\u00e4\u00e4, and R. Uola, Colloquium: Incompatible measurements in quantum information science, Rev. Mod. Phys. 95, 011003 (2023).","DOI":"10.1103\/RevModPhys.95.011003"},{"key":"102","doi-asserted-by":"publisher","unstructured":"R. W. Spekkens, Contextuality for preparations, transformations, and unsharp measurements, Phys. Rev. A 71, 052108 (2005).","DOI":"10.1103\/PhysRevA.71.052108"},{"key":"103","doi-asserted-by":"publisher","unstructured":"D. Schmid, J. H. Selby, M. F. Pusey, and R. W. Spekkens, A structure theorem for generalized-noncontextual ontological models, Quantum 8, 1283 (2024).","DOI":"10.22331\/q-2024-03-14-1283"},{"key":"104","doi-asserted-by":"publisher","unstructured":"A. Streltsov, G. Adesso, and M. B. Plenio, Colloquium: Quantum coherence as a resource, Rev. Mod. Phys. 89, 041003 (2017).","DOI":"10.1103\/RevModPhys.89.041003"},{"key":"105","doi-asserted-by":"publisher","unstructured":"E. F. Galv\u00e3o and D. J. Brod, Quantum and classical bounds for two-state overlaps, Phys. Rev. A 101, 062110 (2020).","DOI":"10.1103\/PhysRevA.101.062110"},{"key":"106","doi-asserted-by":"publisher","unstructured":"R. Wagner, R. S. Barbosa, and E. F. Galv\u00e3o, Inequalities witnessing coherence, nonlocality, and contextuality, Phys. Rev. A 109, 032220 (2024).","DOI":"10.1103\/physreva.109.032220"}],"container-title":["Quantum"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/quantum-journal.org\/papers\/q-2026-05-26-2116\/pdf\/","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T07:38:47Z","timestamp":1779781127000},"score":1,"resource":{"primary":{"URL":"https:\/\/quantum-journal.org\/papers\/q-2026-05-26-2116\/"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,26]]},"references-count":107,"URL":"https:\/\/doi.org\/10.22331\/q-2026-05-26-2116","archive":["CLOCKSS"],"relation":{},"ISSN":["2521-327X"],"issn-type":[{"value":"2521-327X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,26]]},"article-number":"2116"}}