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Related papers: Wigner's friend in context

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"Wigner's friend" refers to a quantum process of which different observers, following the rules of quantum mechanics, give contradictory descriptions. Lostaglio and Bowles have recently claimed to describe a classical system showing the…

Quantum Physics · Physics 2022-01-12 Anthony Sudbery

Proietti et al. (arXiv:1902.05080) reported on an experiment designed to settle, or at least to throw light upon, the paradox of Wigner's friend. Without questioning the rigor or ingenuity of the experimental protocol, I argue that its…

Quantum Physics · Physics 2019-10-29 Louis Marchildon

The measurement problem is seen as an ambiguity of quantum mechanics, or, beyond that, as a contradiction within the theory: Quantum mechanics offers two conflicting descriptions of the Wigner's-friend experiment. As we argue in this note…

Quantum Physics · Physics 2019-12-09 Arne Hansen , Stefan Wolf

The place and role of an Observer in quantum mechanics has been a subject of an ongoing debate since the theory's inception. Wigner brought this question to the fore in a celebrated scenario in which a super-Observer observes a Friend…

Quantum Physics · Physics 2020-09-14 A. Matzkin , D. Sokolovski

The Wigner's friend thought experiment was intended to illustrate the difficulty one has in describing an agent as a quantum system when that agent performs a measurement. While it does pose a challenge to the orthodox interpretation of…

Quantum Physics · Physics 2024-09-12 David Schmid , Yìlè Yīng , Matthew Leifer

I correct two misapprehensions, one historical and one conceptual, in the recent literature on extensions of the Wigner's Friend thought-experiment. Perhaps fittingly, both concern the accurate description of some quantum physicists'…

Quantum Physics · Physics 2019-07-18 Blake C. Stacey

There has been an upsurge of interest in the consequences for quantum physics of the so-called Wigner's Friend Paradox. In its original formulation, the paradox has been turned inside out, and virtually every aspect of it has been looked…

Quantum Physics · Physics 2026-05-28 Julio C. F. Silva , B. F. Rizzuti , Cristhiano Duarte

We take a fresh look at Wigner's Friend thought-experiment and some of its more recent variants and extensions, such as the Frauchiger-Renner (FR) Paradox. We discuss various solutions proposed in the literature, focusing on a few…

Quantum Physics · Physics 2024-04-09 Alexandru Baltag , Sonja Smets

There has been a surge of recent interest in the Wigner's Friend paradox, sparking several novel thought experiments and no-go theorems. The main narrative has been that Wigner's Friend highlights a counterintuitive feature that is unique…

Quantum Physics · Physics 2025-01-22 Caroline L. Jones , Markus P. Mueller

The paradox of Wigner's friend challenges the objectivity of description in quantum theory. A pragmatist interpretation can meet this challenge by judicious appeal to decoherence. On this interpretation, quantum theory provides situated…

Quantum Physics · Physics 2023-06-22 Richard Healey

It is commonly expected that quantum theory is universal, in that it describes the world at all scales. Yet, quantum effects at the macroscopic scale continue to elude our experimental observation. This fact is commonly attributed to…

Wigner's friend experiment and its modern extensions display the ambiguity of the quantum mechanical description regarding the assignment of quantum states. While the friend applies the state-update rule to the system upon observing an…

Quantum Physics · Physics 2025-10-22 Flavio Del Santo , Gonzalo Manzano , Caslav Brukner

The extended Wigner's friend problem deals with two Observers each measuring a sealed laboratory in which a friend is making a quantum measurement. We investigate this problem by relying on the basic rules of quantum mechanics as exposed by…

Quantum Physics · Physics 2021-10-19 D. Sokolovski , A. Matzkin

The Wigner's friend paradox concerns one of the most puzzling problems of quantum mechanics: the consistent description of multiple nested observers. Recently, a variation of Wigner's gedankenexperiment, introduced by Frauchiger and Renner,…

The Wigner's friend experiment is a thought experiment in which a so-called superobserver (Wigner) observes another observer (the friend) who has performed a quantum measurement on a physical system. In this setup Wigner treats the friend,…

Quantum Physics · Physics 2024-09-25 Veronika Baumann , Časlav Brukner

The famous Wigner's friend experiment considers an observer -- the friend -- and a superobserver -- Wigner -- who treats the friend as a quantum system and her interaction with other quantum systems as unitary dynamics. This is at odds with…

Quantum Physics · Physics 2023-10-10 Veronika Baumann

This article suggests that thinking about the role of reference frames can provide new insight into Extended Wigner's Friend scenarios. This involves appealing to symmetries to make a principled distinction between properties of a system…

Quantum Physics · Physics 2025-12-09 Emily Adlam

We present a discussion of the extended Wigner's friend thought experiment proposed by Frauchiger and Renner in [1]. We show by using various arguments, including textbook quantum mechanics and the ontological approach of Contexts, Systems,…

Quantum Physics · Physics 2023-01-10 Maxime Federico , Philippe Grangier

The Wigner's friend type of thought experiments manifest the conceptual challenge on how different observers can have consistent descriptions of a quantum measurement event. In this paper, we analyze the extended version of Wigner's friend…

Quantum Physics · Physics 2019-11-12 Jianhao M. Yang

The concept of an isolated system, and Frauchiger and Renner's extended `Wigner's friend' scenario are discussed. It is argued that: (i) it is questionable whether the approximation of the isolated system is valid when measurement-like…

Quantum Physics · Physics 2026-05-12 Andrew Steane
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