scholarly journals Contextual Inferences, Nonlocality, and the Incompleteness of Quantum Mechanics

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1660
Author(s):  
Philippe Grangier
Keyword(s):  
Quantum Mechanics ◽  
Quantum State ◽  
Hidden Variables ◽  
Point Of View ◽  
Local Realism ◽  
Quantum Non Locality ◽  
Relativistic Causality ◽  
Usual Quantum ◽  
Measurement Context ◽  
Non Locality

It is known that “quantum non locality”, leading to the violation of Bell’s inequality and more generally of classical local realism, can be attributed to the conjunction of two properties, which we call here elementary locality and predictive completeness. Taking this point of view, we show again that quantum mechanics violates predictive completeness, allowing the making of contextual inferences, which can, in turn, explain why quantum non locality does not contradict relativistic causality. An important question remains: if the usual quantum state ψ is predictively incomplete, how do we complete it? We give here a set of new arguments to show that ψ should be completed indeed, not by looking for any “hidden variables”, but rather by specifying the measurement context, which is required to define actual probabilities over a set of mutually exclusive physical events.

Locality or Non-Locality in Quantum Mechanics: Hidden Variables without "Spooky Action-at-a-Distance"

2001 ◽  
Vol 56 (1-2) ◽  
pp. 5-15
Author(s):  
Yakir Aharonov ◽  
Alonso Botero ◽  
Marian Scully
Keyword(s):  
Quantum Mechanics ◽  
Hidden Variables ◽  
Point Of View ◽  
Quantum Mechanical ◽  
The Third ◽  
Pacs 03.65 ◽  
Action At A Distance ◽  
Non Locality

Abstract The folklore notion of the "Non-Locality of Quantum Mechanics" is examined from the point of view of hidden-variables theories according to Belinfante's classification in his Survey of Hidden Variables Theories. It is here shown that in the case of EPR, there exist hidden variables theories that successfully reproduce quantum-mechanical predictions, but which are explicitly local. Since such theories do not fall into Belinfante's classification, we propose an expanded classification which includes similar theories, which we term as theories of the "third" kind. Causal implications of such theories are explored. -Pacs: 03.65.Bz

Quantum Becoming?

2017 ◽  
Author(s):  
Craig Callender
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Quantum Time ◽  
Quantum Non Locality ◽  
Time Quantum ◽  
Temporal Becoming ◽  
Non Locality ◽  
Quantum Wavefunction

Two of quantum mechanics’ more famed and spooky features have been invoked in defending the idea that quantum time is congenial to manifest time. Quantum non-locality is said by some to make a preferred foliation of spacetime necessary, and the collapse of the quantum wavefunction is held to vindicate temporal becoming. Although many philosophers and physicists seek relief from relativity’s assault on time in quantum theory, assistance is not so easily found.

THOUGHTS ON NON-LOCALITY AND QUANTUM MECHANICS

2006 ◽  
Vol 04 (01) ◽  
pp. 209-218 ◽  
Author(s):  
W. UNRUH
Keyword(s):  
Quantum Mechanics ◽  
20Th Century ◽  
Additional Assumption ◽  
Hidden Variables ◽  
Late 20Th Century ◽  
Hardy Type ◽  
Non Local ◽  
The Difference ◽  
Numerous People ◽  
Non Locality

The debate about the non-locality of quantum mechanics is old, but still lively. Numerous people use non-locality as (bad) shorthand for quantum entanglement. But some have a long-standing commitment to the validity of this characterization. This paper examines two separate streams in this debate. The first is the arguments of Stapp, and especially his recent paper where he simplifies his contractual argument in the Hardy situation to argue for the non-locality of quantum mechanics. He has maintained his contention that an analysis of a Hardy-type correlation between two spatially separated observers proves that quantum mechanics itself is non-local, without any additional assumption of realism or hidden variables. In the second section, I try to carefully examine the Bell argument in the CHSH variant to see where the difference between the quantum and classical situations differ. Asher Peres was one of the great physicists of the late 20th century, especially for his intense concern with the fundamental nature of quantum mechanics. His courage in devoting his life to an area many considered "philosophical" (i.e. non-physical) paved the way for the rest of us to reveal our interests and confusions about this area. I am not sure that he would agree with everything in this paper, but I offer it as a tribute to him.

scholarly journals ON CLASSICAL TELEPORTATION AND CLASSICAL NON-LOCALITY

2006 ◽  
Vol 04 (01) ◽  
pp. 161-171 ◽  
Author(s):  
TAL MOR
Keyword(s):  
Probability Distribution ◽  
Point Of View ◽  
Entangled State ◽  
Classical Information ◽  
The North ◽  
Classical State ◽  
Quantum Non Locality ◽  
Classical Analogue ◽  
Processing Point ◽  
Non Locality

An interesting protocol for classical teleportation of an unknown classical state was recently suggested by Cohen, and by Gour and Meyer. In that protocol, Bob can sample from a probability distribution [Formula: see text] that is given to Alice, even if Alice has absolutely no knowledge about [Formula: see text]. Pursuing a similar line of thought, we suggest here a limited form of non-locality — "classical non-locality." Our non-locality is the (somewhat limited) classical analogue of the Hughston–Jozsa–Wootters (HJW) quantum non-locality. The HJW non-locality (also known as "quantum remote steering") tells us how, for a given density matrix ρ, Alice can generate any ρ-ensemble on the North Star. This is done using surprisingly few resources — one shared entangled state (prepared in advance), one generalized quantum measurement, and no communication. Similarly, our classical non-locality (which we call "classical remote steering") presents how, for a given probability distribution [Formula: see text], Alice can generate any [Formula: see text]-ensemble on the North Star, using only one correlated state (prepared in advance), one (generalized) classical measurement, and no communication. It is important to clarify that while the classical teleportation and the classical non-locality protocols are probably rather insignificant from a classical information processing point of view, they significantly contribute to our understanding of what exactly is quantum in their well established and highly famous quantum analogues.

QBism: An Analytical Review

2020 ◽  
Vol 57 (4) ◽  
pp. 199-216
Author(s):  
Alexander A. Pechenkin ◽  
Keyword(s):  
Quantum Mechanics ◽  
Quantum State ◽  
Theory Of Measurement ◽  
Copenhagen Interpretation ◽  
Point Of View ◽  
Interpretation Of Quantum Mechanics ◽  
Quantum Processes ◽  
Quantum Superposition ◽  
Analytical Review ◽  
New Interpretation

A new interpretation of quantum mechanics, the interpretation which became popular in XXI, has been taken under consideration. This is the quantum baysinism (QBism) which may be taken as an extrapolation of the baysian philosophy of probability over the interpretation of quantum mechanics. The baysian philosophy of quantum mechanics has been compared with the Copenhagen interpretation of quantum mechanics, the interpretation which can been treated as standard as it is represented in the main textbooks. In contrast to the Copenhagen interpretation which proceeds from the triplets – nature, apparatus and observer (agent), QBism emphasizes the conscious of the observer: the quantum state is the observer’s state, and by means of the quantum conceptual technique the observer constructs his/her own image of quantum processes. By means of measurement the observer updates his/her quantum state, the measuring apparatus being an extension of the observer’s sensuality. From the point of the QBism’s view the phenomenon of decoherence which is widely discussed in the contemporary literature is not essential for the theory of measurement in quantum mechanics. The decoherence explains why the macroscopic phenomena don’t expose the interference behavior which is characteristic for quantum superposition. From the historicо-philosophical point of view Qbism can be traced back to American instrumentalism and operationalism.

scholarly journals Quantum Correlations and Quantum Non-Locality: A Review and a Few New Ideas

2019 ◽  
Vol 9 (24) ◽  
pp. 5406 ◽  
Author(s):  
Marco Genovese ◽  
Marco Gramegna
Keyword(s):  
Quantum Mechanics ◽  
Special Relativity ◽  
Quantum Correlations ◽  
Quantum Non Locality ◽  
Higher Dimensional ◽  
New Ideas ◽  
Non Locality

In this paper we make an extensive description of quantum non-locality, one of the most intriguing and fascinating facets of quantum mechanics. After a general presentation of several studies on this subject dealing with different but connected facets of quantum non-locality, we consider if this, and the friction it carries with special relativity, can eventually find a “solution” by considering higher dimensional spaces.

scholarly journals Quantum Entanglement Results from Quantum State Transition at Fast-Than-Light Speed with Matter Wave’s Phase Velocity

2021 ◽  
Vol 5 (2) ◽  
pp. 1-4
Author(s):  
Wang Xinye
Keyword(s):  
Quantum Mechanics ◽  
Phase Velocity ◽  
Quantum Entanglement ◽  
Quantum State ◽  
State Transition ◽  
Local Realism ◽  
Classical Physics ◽  
Speed Difference ◽  
Light Speed

The quantum entanglement, that violates the local realism and other classical physics theories, leads to various counterintuitive phenomena, is a primary feature of quantum mechanics and probably results from the quantum state’s conservation and the quantum state’s transition with the matter wave’s phase velocity at the fast-than-light speed. The quantum state transition of entangled particles proceeds with the phase velocity, while the observer measures the process with the electromagnetic or the light speed. This speed difference makes the causality law no longer fully valid everywhere except in certain areas.

scholarly journals Particle physics violating crypto-nonlocal realism

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Yu Shi ◽  
Ji-Chong Yang
Keyword(s):  
Quantum Mechanics ◽  
Cp Violation ◽  
Particle Physics ◽  
Hidden Variables ◽  
Bell Inequalities ◽  
Charge Conjugation ◽  
Local Realism ◽  
Experimental Result ◽  
Charge Conjugation Parity ◽  
Cp Symmetry

AbstractIt has been well established that quantum mechanics (QM) violates Bell inequalities (BI), which are consequences of local realism (LR). Remarkably QM also violates Leggett inequalities (LI), which are consequences of a class of nonlocal realism called crypto-nonlocal realism (CNR). Both LR and CNR assume that measurement outcomes are determined by preexisting objective properties, as well as hidden variables (HV) not considered in QM. We extend CNR and LI to include the case that the measurement settings are not externally fixed, but determined by HV. We derive a new version of LI, which is then shown to be violated by entangled $$B_d$$ B d mesons, if charge–conjugation–parity (CP) symmetry is indirectly violated, as indeed established. The experimental result is quantitatively estimated by using the indirect CP violation parameters, and the maximum of a suitably defined relative violation is about $$2.7\%$$ 2.7 % . Our work implies that particle physics violates CNR. Our LI can also be tested in other systems such as photon polarizations.

scholarly journals Violation of Bell’s inequalities in a quantum realistic framework

2016 ◽  
Vol 14 (04) ◽  
pp. 1640002 ◽  
Author(s):  
Alexia Auffèves ◽  
Philippe Grangier
Keyword(s):  
Quantum Mechanics ◽  
Physical Properties ◽  
Point Of View ◽  
Bell’S Inequalities ◽  
Quantum Realism ◽  
Action At A Distance ◽  
Classical Realism ◽  
Bell's Inequalities ◽  
Non Locality ◽  
Realist View

We discuss the recently observed “loophole free” violation of Bell’s inequalities in the framework of a physically realist view of quantum mechanics (QM), which requires that physical properties are attributed jointly to a system, and to the context in which it is embedded. This approach is clearly different from classical realism, but it does define a meaningful “quantum realism” from a general philosophical point of view. Consistently with Bell test experiments, this quantum realism embeds some form of non-locality, but does not contain any action at a distance, in agreement with QM.

scholarly journals QUANTUM SINGULARITIES IN STATIC SPACETIMES

2011 ◽  
Vol 20 (05) ◽  
pp. 729-743 ◽  
Author(s):  
JOÃO PAULO M. PITELLI ◽  
PATRICIO S. LETELIER
Keyword(s):  
Quantum Mechanics ◽  
Wave Operator ◽  
Point Of View ◽  
Quantum Mechanical ◽  
Mathematical Framework ◽  
Physical Content ◽  
Dirac Equations ◽  
Quantum Particles ◽  
Klein Gordon ◽  
Quantum Singularities

We review the mathematical framework necessary to understand the physical content of quantum singularities in static spacetimes. We present many examples of classical singular spacetimes and study their singularities by using wave packets satisfying Klein–Gordon and Dirac equations. We show that in many cases the classical singularities are excluded when tested by quantum particles but unfortunately there are other cases where the singularities remain from the quantum mechanical point of view. When it is possible we also find, for spacetimes where quantum mechanics does not exclude the singularities, the boundary conditions necessary to turn the spatial portion of the wave operator to be self-adjoint and emphasize their importance to the interpretation of quantum singularities.

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