Connecting extended Wigner's friend arguments and noncontextuality
The Local Friendliness argument is an extended Wigner's friend no-go theorem that provides strong constraints on the nature of reality – stronger even than those imposed by Bell's theorem or by noncontextuality arguments. In this work, we prove a variety of connections between Local Friend...
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| Format: | Article |
| Language: | English |
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Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
2025-07-01
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| Series: | Quantum |
| Online Access: | https://quantum-journal.org/papers/q-2025-07-31-1819/pdf/ |
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| author | Laurens Walleghem Yìlè Yīng Rafael Wagner David Schmid |
| author_facet | Laurens Walleghem Yìlè Yīng Rafael Wagner David Schmid |
| author_sort | Laurens Walleghem |
| collection | DOAJ |
| description | The Local Friendliness argument is an extended Wigner's friend no-go theorem that provides strong constraints on the nature of reality – stronger even than those imposed by Bell's theorem or by noncontextuality arguments. In this work, we prove a variety of connections between Local Friendliness scenarios and Kochen-Specker noncontextuality. Specifically, we first show how one can derive new Local Friendliness inequalities using known tools and results from the literature on Kochen-Specker noncontextuality. In doing so, we provide a new derivation for some of the facets of the Local Friendliness polytope, and we prove that this polytope is equal to the Bell polytope in a wide range of extended Wigner's friend scenarios with multipartite agents and sequential measurements. We then show how any possibilistic Kochen-Specker argument can be mathematically translated into a related proof of the Local Friendliness no-go theorem. In particular, we construct a novel kind of Local Friendliness scenario where a friend implements several compatible measurements (or joint measurements of these) in between the superobserver's operations on them. We illustrate this with the well-known 5-cycle and Peres-Mermin contextuality arguments. |
| format | Article |
| id | doaj-art-b12e10e92c4c4c8fb465d636b850c83c |
| institution | Matheson Library |
| issn | 2521-327X |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften |
| record_format | Article |
| series | Quantum |
| spelling | doaj-art-b12e10e92c4c4c8fb465d636b850c83c2025-07-31T11:23:42ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2025-07-019181910.22331/q-2025-07-31-181910.22331/q-2025-07-31-1819Connecting extended Wigner's friend arguments and noncontextualityLaurens WalleghemYìlè YīngRafael WagnerDavid SchmidThe Local Friendliness argument is an extended Wigner's friend no-go theorem that provides strong constraints on the nature of reality – stronger even than those imposed by Bell's theorem or by noncontextuality arguments. In this work, we prove a variety of connections between Local Friendliness scenarios and Kochen-Specker noncontextuality. Specifically, we first show how one can derive new Local Friendliness inequalities using known tools and results from the literature on Kochen-Specker noncontextuality. In doing so, we provide a new derivation for some of the facets of the Local Friendliness polytope, and we prove that this polytope is equal to the Bell polytope in a wide range of extended Wigner's friend scenarios with multipartite agents and sequential measurements. We then show how any possibilistic Kochen-Specker argument can be mathematically translated into a related proof of the Local Friendliness no-go theorem. In particular, we construct a novel kind of Local Friendliness scenario where a friend implements several compatible measurements (or joint measurements of these) in between the superobserver's operations on them. We illustrate this with the well-known 5-cycle and Peres-Mermin contextuality arguments.https://quantum-journal.org/papers/q-2025-07-31-1819/pdf/ |
| spellingShingle | Laurens Walleghem Yìlè Yīng Rafael Wagner David Schmid Connecting extended Wigner's friend arguments and noncontextuality Quantum |
| title | Connecting extended Wigner's friend arguments and noncontextuality |
| title_full | Connecting extended Wigner's friend arguments and noncontextuality |
| title_fullStr | Connecting extended Wigner's friend arguments and noncontextuality |
| title_full_unstemmed | Connecting extended Wigner's friend arguments and noncontextuality |
| title_short | Connecting extended Wigner's friend arguments and noncontextuality |
| title_sort | connecting extended wigner s friend arguments and noncontextuality |
| url | https://quantum-journal.org/papers/q-2025-07-31-1819/pdf/ |
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