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Wigner's friend scenario, Born's rule and an alternative formulation of pilot wave theory

Qian Li

Published Dec 29, 2023• 0 citations
Publisher

Abstract

Abstract In this paper, we analyze the thought experiment of "Wigner's friend" and point out that new understanding should be made to Born's rule and measurement process: Born's rule is no longer seen as a rule based on the history of the quantum system's, and the measurement results are no longer directly related to the state of the measured object before the measurement. Inspired by Everett III and H. Zurek's views, we believe that Born's rule reflects the coordination between states of different parts in quantum entanglement systems, so it has nothing to do with the history of particles themselves but rather with the historical records. A new formulation of pilot wave theory, objective relative state formulation, or ORSF is suggested. Under this interpretation, micro-particles can also be assigned definite states before being observed. Based on this formulation, Wigner's friend-like scenarios can be effectively explained. We also notice that our universe can be totally retrocausal by the new formulation. The new interpretation brings new perspectives to many quantum phenomena.

DOI
10.21203/rs.3.rs-3270399/v4

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Abstract In this paper, we analyze the thought experiment of "Wigner's friend" and point out that new understanding should be made to Born's rule and measurement process: Born's rule is no longer seen as a rule based on the history of the quantum system's, and the measurement results are no longer directly related to the state of the measured object before the measurement. Inspired by Everett III and H. Zurek's views, we believe that Born's rule reflects the coordination between states of different parts in quantum entanglement systems, so it has nothing to do with the history of particles themselves but rather with the historical records. A new formulation of pilot wave theory, objective relative state formulation, or ORSF is suggested. Under this interpretation, micro-particles can also be assigned definite states before being observed. Based on this formulation, Wigner's friend-like scenarios can be effectively explained. We also notice that our universe can be totally retrocausal by the new formulation. The new interpretation brings new perspectives to many quantum phenomena.
Abstract In this paper, we analyze the thought experiment of ”Wigner’s friend” and point out that new understanding should be made to Born’s rule and measurement process: Born’s rule is no longer seen as a rule based on the history of the quantum system’s, and the measurement results are no longer directly related to the state of the measured object before the measurement. Inspired by Everett III and H. Zurek’s views, we believe that Born’s rule reflects the coordination between states of different parts in quantum entanglement systems, so it has nothing to do with the history of particles themselves but rather with the historical records. A new interpretation of quantum mechanics, objective relative state formulation, or ORSF interpretation is proposed, which is a new type of pliot wave theory. Under this interpretation, micro-particles can also be assigned definite states before being observed. Based on this interpretation, Wigner’s friend-like scenarios can be effectively explained. The new interpretation brings new perspectives to many quantum phenomena. We also point out potential applications of the new interpretation in the future.
Abstract In this paper, we analyze the thought experiment of "Wigner's friend" and point out that new understanding should be made to Born's rule and measurement process: Born's rule is no longer seen as a rule based on the history of the quantum system's, and the measurement results are no longer directly related to the state of the measured object before the measurement. Inspired by Everett III and H. Zurek's views, we believe that Born's rule reflects the coordination between different parts of the measured results in quantum entanglement systems, so it has nothing to do with the history of particles themselves but rather with the history records. A new interpretation of quantum mechanics is proposed, which is an objective interpretation. Under this interpretation, micro-particles can also be assigned definite states before being observed. Based on this interpretation, Wigner's friend-like scenarios or paradoxes extending Wigner's friend-like scenarios can be effectively explained. The new interpretation brings brand-new perspectives to many quantum phenomena. We also point out potential applications of the new interpretation in the future.
Abstract In this paper, we analyze the thought experiment of "Wigner's friend" and point out that new understanding should be made to Born's rule and measurement process: Born's rule is no longer seen as a rule based on the history of the quantum system's, and the measurement results are no longer directly related to the state of the measured object before the measurement. Inspired by Everett III and H. Zurek's views, we believe that Born's rule reflects the coordination between different parts of the measured results in quantum entanglement systems, so it has nothing to do with the history of particles themselves but rather with the history records. A new interpretation of quantum mechanics is proposed, which is an objective interpretation. Under this interpretation, micro-particles can also be assigned definite states before being observed. Based on this interpretation, Wigner's friend-like scenarios or paradoxes extending Wigner's friend-like scenarios can be effectively explained. The new interpretation brings brand-new perspectives to many quantum phenomena. We also point out potential applications of the new interpretation in the future.
By assuming (i) a universal, observer-independent quantum state, by considering (ii) measurement processes with wave function collapse as part of quantum mechanical time evolution (also within isolated systems), and by (iii) clearly distinguishing the state of a quantum system from the knowledge of conscious observers about this state, we suggest a modified Copenhagen interpretation of quantum mechanics that resolves Wigner's Friend and extended Wigner's Friend paradoxes. The suggested interpretation leads to differences in some outcome probabilities compared to previous analyses which, in principle, make it possible to falsify the suggested modifications or the previous analyses (or both). The fundamental problem of the incompleteness of quantum mechanics in the Copenhagen interpretation regarding the lack of a precise definition and a mechanistic description of the measurement process (including the collapse of the wave function) is not addressed in this study. However, the argumentation regarding the resolution of Wigner's Friend paradoxes also applies to attempts for such a mechanistic description using collapse models with stochastic extensions to the Schrödinger equation or trying to model wave function collapse with unitary time evolution and irreversibility of the measurement process resulting from quantum statistical mechanics.
Abstract The notorious Wigner’s friend thought experiment (and modifications thereof) has received renewed interest especially due to new arguments that force us to question some of the fundamental assumptions of quantum theory. In this paper, we formulate a no-go theorem for the persistent reality of Wigner’s friend’s perception, which allows us to conclude that the perceptions that the friend has of her own measurement outcomes at different times cannot “share the same reality”, if seemingly natural quantum mechanical assumptions are met. More formally, this means that, in a Wigner’s friend scenario, there is no joint probability distribution for the friend’s perceived measurement outcomes at two different times, that depends linearly on the initial state of the measured system and whose marginals reproduce the predictions of unitary quantum theory. This theorem entails that one must either (1) propose a nonlinear modification of the Born rule for two-time predictions, (2) sometimes prohibit the use of present information to predict the future—thereby reducing the predictive power of quantum theory—or (3) deny that unitary quantum mechanics makes valid single-time predictions for all observers. We briefly discuss which of the theorem’s assumptions are more likely to be dropped within various popular interpretations of quantum mechanics.
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 outcome of her measurement in a quantum system, Wigner describes the friend’s measurement as a unitary evolution, resulting in an entangled state for the composite system of the friend and the system. In this respect, Wigner is often referred to as a “superobserver,” who has the supreme technological ability to keep the friend’s laboratory coherent. As such, it is often argued that he has the “correct” description of the state. Here, we show that the situation is more symmetrical than is usually thought: There are different types of information that each of the observers has that the other fundamentally cannot have—they reside in different “bubbles” (in Cavalcanti’s terminology). While this can explain why the objectivity of the state assignment is only relative to the bubble, we consider more elaborated situations in the form of a game in which the players can switch between bubbles. We find that, in certain circumstances, observers may be entitled to adopt and verify the state assignment from another bubble if they condition their predictions on information that is in principle available to them.