Any theory that admits a Wigner's Friend type multi-agent paradox is logically contextual

• URL: http://arxiv.org/abs/2502.03874v1
• Date: Thu, 06 Feb 2025 08:43:36 GMT
• Title: Any theory that admits a Wigner's Friend type multi-agent paradox is logically contextual
• Authors: Nuriya Nurgalieva, V. Vilasini,
• Abstract summary: We prove a link between Wigner's Friend type multi-agent paradoxes and contextuality in general theories. We identify structural properties of such paradoxes in general theories and specific to quantum theory.
• Score: 0.0
• License:
• Abstract: Wigner's Friend scenarios push the boundaries of quantum theory by modeling agents, along with their memories storing measurement outcomes, as physical quantum systems. Extending these ideas beyond quantum theory, we ask: in which physical theories, and under what assumptions, can agents who are reasoning logically about each other's measurement outcomes encounter apparent paradoxes? To address this, we prove a link between Wigner's Friend type multi-agent paradoxes and contextuality in general theories: if agents who are modeled within a physical theory come to a contradiction when reasoning using that theory (under certain assumptions on how they reason and describe measurements), then the theory must admit contextual correlations of a logical form. This also yields a link between the distinct fundamental concepts of Heisenberg cuts and measurement contexts in general theories, and in particular, implies that the quantum Frauchiger-Renner paradox is a proof of logical contextuality. Moreover, we identify structural properties of such paradoxes in general theories and specific to quantum theory. For instance, we demonstrate that theories admitting behaviors corresponding to extremal vertices of n-cycle contextuality scenarios admit Wigner's Friend type paradoxes without post-selection, and that any quantum Wigner's Friend paradox based on the n-cycle scenario must necessarily involve post-selection. Further, we construct a multi-agent paradox based on a genuine contextuality scenario involving sequential measurements on a single system, showing that Bell non-local correlations between distinct subsystems are not necessary for Wigner's Friend paradoxes. Our work offers an approach to investigate the structure of physical theories and their information-theoretic resources by means of deconstructing the assumptions underlying multi-agent physical paradoxes.

Related papers

• A refined Frauchiger--Renner paradox based on strong contextuality [0.0]
  We observe that logical contextuality is the key ingredient of the FR paradox. We propose a natural extension of Peres's dictum to resolve these extended Wigner's friend paradoxes.
  arXiv  Detail & Related papers  (2024-09-09T10:36:47Z)
• Minimal operational theories: classical theories with quantum features [41.94295877935867]
  We introduce a class of probabilistic theories, where system dynamics are constrained to the minimal set of operations. Specifically, the allowed instruments are limited to those derived from compositions of preparations, measurements, swap transformations, and conditional tests. We demonstrate that minimal theories with conditioning and a spanning set of non-separable states satisfy two quantum no-go theorems.
  arXiv  Detail & Related papers  (2024-08-02T16:24:09Z)
• Generalized Einstein-Podolsky-Rosen Steering Paradox [18.5699135339787]
  We present a generalized EPR steering paradox, which predicts a contradictory equality $2_Q=left( 1+deltaright)_C$. We test the paradox through a two-setting steering protocol, and find that the state is steerable if some specific measurement requirements are satisfied. Our construction also enlightens the building of EPR steering inequality, which may contribute to some schemes for typical quantum teleportation and quantum key distributions.
  arXiv  Detail & Related papers  (2024-05-06T01:25:11Z)
• On the significance of Wigner's Friend in contexts beyond quantum foundations [0.0]
  Wigner's Friend highlights a counterintuitive feature that is unique to quantum theory. We argue that the gist of the Wigner's Friend paradox can be reproduced without assuming quantum physics.
  arXiv  Detail & Related papers  (2024-02-13T19:00:13Z)
• Logic meets Wigner's Friend (and their Friends) [49.1574468325115]
  We take a fresh look at Wigner's Friend thought-experiment and some of its more recent variants and extensions. We discuss various solutions proposed in the literature, focusing on a few questions.
  arXiv  Detail & Related papers  (2023-07-04T13:31:56Z)
• Connecting classical finite exchangeability to quantum theory [45.76759085727843]
  Exchangeability is a fundamental concept in probability theory and statistics. It allows to model situations where the order of observations does not matter. It is well known that both theorems do not hold for finitely exchangeable sequences.
  arXiv  Detail & Related papers  (2023-06-06T17:15:19Z)
• Quantum Theory Needs (And Probably Has) Real Reduction [0.0]
  It appears that for quantum theory to be viable in a realist sense, it must possess genuine, physical non-unitarity. Penrose's theory of gravitation-induced collapse and the Transactional Interpretation are discussed.
  arXiv  Detail & Related papers  (2023-04-20T21:25:23Z)
• Quantum indistinguishability through exchangeable desirable gambles [69.62715388742298]
  Two particles are identical if all their intrinsic properties, such as spin and charge, are the same. Quantum mechanics is seen as a normative and algorithmic theory guiding an agent to assess her subjective beliefs represented as (coherent) sets of gambles. We show how sets of exchangeable observables (gambles) may be updated after a measurement and discuss the issue of defining entanglement for indistinguishable particle systems.
  arXiv  Detail & Related papers  (2021-05-10T13:11:59Z)
• Observers of quantum systems cannot agree to disagree [55.41644538483948]
  We ask whether agreement between observers can serve as a physical principle that must hold for any theory of the world. We construct examples of (postquantum) no-signaling boxes where observers can agree to disagree.
  arXiv  Detail & Related papers  (2021-02-17T19:00:04Z)
• The original Wigner's friend paradox within a realist toy model [0.0]
  The original Wigner's friend paradox highlights the tension between unitary evolution and collapse in quantum theory. We present a classical toy model in which the contradicting predictions at the heart of the thought experiment are reproduced. The debate surrounding the original Wigner's friend thought experiment and its resolution have striking similarities with arguments concerning the nature of the second law of thermodynamics.
  arXiv  Detail & Related papers  (2021-01-26T19:03:32Z)
• Unitary-Only Quantum Theory Cannot Consistently Describe the Use of Itself: On the Frauchiger-Renner Paradox [0.0]
  The Frauchiger-Renner Paradox is an extension of paradoxes based on the 'Problem of Measurement,' such as Schrodinger's Cat and Wigner's Friend. This paper discusses a basic inconsistency arising in the FR scenario at a much earlier point than the derived contradiction.
  arXiv  Detail & Related papers  (2020-02-04T18:34:20Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.