scholarly journals ARE QUANTUM CORRELATIONS GENUINELY QUANTUM?

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345016 ◽  
Author(s):  
ANTONIO DI LORENZO
Keyword(s):  
Detection Efficiency ◽  
Hidden Variables ◽  
Random Variables ◽  
Quantum Correlations ◽  
Random Mechanism ◽  
Spin Singlet ◽  
Action At A Distance ◽  
Probability Decomposition

It is shown that the probabilities for the spin singlet can be reproduced through classical resources, with no communication between the distant parties, by using merely shared (pseudo-)randomness. If the parties are conscious beings aware of both the hidden-variables and the random mechanism, then one has a conspiracy. If the parties are aware of only the random variables, they may be induced to believe that they are able to send instantaneous information to one another. It is also possible to reproduce the correlations at the price of reducing the detection efficiency. It is further demonstrated that the same probability decomposition could be realized through action-at-a-distance, provided it existed.

scholarly journals Nonrecurrence and Bell-like inequalities

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 762-768
Author(s):  
Douglas G. Danforth
Keyword(s):  
Infinite Number ◽  
General Class ◽  
Hidden Variables ◽  
Random Variables ◽  
Random Variable ◽  
Bell Inequalities ◽  
Usual Sense ◽  
Real Random Variable ◽  
Action At A Distance ◽  
The Continuum

AbstractThe general class,Λ, of Bell hidden variables is composed of two subclassesΛRandΛNsuch thatΛR⋃ΛN=ΛandΛR∩ΛN= {}. The classΛNis very large and contains random variables whose domain is the continuum, the reals. There are an uncountable infinite number of reals. Every instance of a real random variable is unique. The probability of two instances being equal is zero, exactly zero.ΛNinduces sample independence. All correlations are context dependent but not in the usual sense. There is no “spooky action at a distance”. Random variables, belonging toΛN, are independent from one experiment to the next. The existence of the classΛNmakes it impossible to derive any of the standard Bell inequalities used to define quantum entanglement.

scholarly journals Computing conditional entropies for quantum correlations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peter Brown ◽  
Hamza Fawzi ◽  
Omar Fawzi
Keyword(s):  
Quantum Key Distribution ◽  
Detection Efficiency ◽  
Conditional Entropy ◽  
Key Distribution ◽  
Quantum Correlations ◽  
Upper Bounds ◽  
Cryptographic Protocols ◽  
Quantum States ◽  
Security Proofs

AbstractThe rates of quantum cryptographic protocols are usually expressed in terms of a conditional entropy minimized over a certain set of quantum states. In particular, in the device-independent setting, the minimization is over all the quantum states jointly held by the adversary and the parties that are consistent with the statistics that are seen by the parties. Here, we introduce a method to approximate such entropic quantities. Applied to the setting of device-independent randomness generation and quantum key distribution, we obtain improvements on protocol rates in various settings. In particular, we find new upper bounds on the minimal global detection efficiency required to perform device-independent quantum key distribution without additional preprocessing. Furthermore, we show that our construction can be readily combined with the entropy accumulation theorem in order to establish full finite-key security proofs for these protocols.

scholarly journals Classical (Local and Contextual) Probability Model for Bohm–Bell Type Experiments: No-Signaling as Independence of Random Variables

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 157 ◽  
Author(s):  
Andrei Khrennikov ◽  
Alexander Alodjants
Keyword(s):  
Conditional Probability ◽  
Probability Model ◽  
Hidden Variables ◽  
Random Variables ◽  
Experimental Scheme ◽  
Model Following ◽  
No Signaling ◽  
Independence Of Random Variables ◽  
Main Message ◽  
Selection Of

We start with a review on classical probability representations of quantum states and observables. We show that the correlations of the observables involved in the Bohm–Bell type experiments can be expressed as correlations of classical random variables. The main part of the paper is devoted to the conditional probability model with conditioning on the selection of the pairs of experimental settings. From the viewpoint of quantum foundations, this is a local contextual hidden-variables model. Following the recent works of Dzhafarov and collaborators, we apply our conditional probability approach to characterize (no-)signaling. Consideration of the Bohm–Bell experimental scheme in the presence of signaling is important for applications outside quantum mechanics, e.g., in psychology and social science. The main message of this paper (rooted to Ballentine) is that quantum probabilities and more generally probabilities related to the Bohm–Bell type experiments (not only in physics, but also in psychology, sociology, game theory, economics, and finances) can be classically represented as conditional probabilities.

QUANTUM CORRELATIONS IN THE "q-DEFORMED" WERNER STATE

2013 ◽  
Vol 11 (02) ◽  
pp. 1350018 ◽  
Author(s):  
BO LIU ◽  
KANG XUE ◽  
GANGCHENG WANG ◽  
CHUNFANG SUN ◽  
LIDAN GOU ◽  
...  
Keyword(s):  
Quantum Discord ◽  
Singlet State ◽  
Great Influence ◽  
Quantum Correlations ◽  
Werner State ◽  
Single Loop ◽  
Geometric Measure ◽  
Topological Parameter ◽  
Spin Singlet ◽  
Two Parameters

We investigate quantum discord of the "q-deformed" Werner state via Yang–Baxterization approach. There are two parameters q and u in this "q-deformed" Werner state. The parameter u, which plays an important role in some typical models, is related to the probability of the "q-deformed" two-qubit spin singlet state in this study. The "q-deformed" parameter q is related to the single loop through d = q + q-1. When topological parameter d approaches 2 (i.e. q → 1), the "q-deformed" Werner state degenerates into the well-known Werner state. The results show that topological parameter d has great influence on quantum correlations of the "q-deformed" Werner state. When we fix the parameter u, the quantum correlations decrease with increasing the single loop d. When d approaches +∞ (i.e. q → 0+ or +∞), quantum discord, geometric measure of quantum discord and entanglement all tend to 0. While d approaches 2 (i.e. q → 1), all of them just have the same results with the Werner state.

scholarly journals Single-shot energetic-based estimator for entanglement in a half-parity measurement setup

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 166 ◽  
Author(s):  
Cyril Elouard ◽  
Alexia Auffèves ◽  
Géraldine Haack
Keyword(s):  
Information Technologies ◽  
Detection Efficiency ◽  
Quantum Correlations ◽  
Quantum Trajectory ◽  
Single Shot ◽  
Thermodynamic Quantities ◽  
The Road ◽  
Trajectory Approach ◽  
New Strategy ◽  
Parity Measurement

Producing and certifying entanglement between distant qubits is a highly desirable skill for quantum information technologies. Here we propose a new strategy to monitor and characterize entanglement genesis in a half parity measurement setup, that relies on the continuous readout of an energetic observable which is the half-parity observable itself. Based on a quantum-trajectory approach, we theoretically analyze the statistics of energetic fluctuations for a pair of continuously monitored qubits. We quantitatively relate these energetic fluctuations to the rate of entanglement produced between the qubits, and build an energetic-based estimator to assess the presence of entanglement in the circuit. Remarkably, this estimator is valid at the single-trajectory level and shows to be robust against finite detection efficiency. Our work paves the road towards a fundamental understanding of the stochastic energetic processes associated with entanglement genesis, and opens new perspectives for witnessing quantum correlations thanks to quantum thermodynamic quantities.

scholarly journals Proposal to Test a Transient Deviation from Quantum Mechanics’ Predictions for Bell’s Experiment

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1589
Author(s):  
Alejandro Andrés Hnilo ◽  
Monica Beatriz Agüero ◽  
Marcelo Gregorio Kovalsky
Keyword(s):  
Quantum Mechanics ◽  
Hidden Variables ◽  
Quantum Correlations ◽  
Entangled State ◽  
Particle Detection ◽  
Specific Test ◽  
Nonlinear Operators ◽  
Model Following ◽  
Proposed Model ◽  
Faster Than Light

Quantum mechanics predicts correlations between measurements performed in distant regions of a spatially spread entangled state to be higher than allowed by intuitive concepts of Locality and Realism. These high correlations forbid the use of nonlinear operators of evolution (which would be desirable for several reasons), for they may allow faster-than-light signaling. As a way out of this situation, it has been hypothesized that the high quantum correlations develop only after a time longer than L/c has elapsed (where L is the spread of the entangled state and c is the velocity of light). In shorter times, correlations compatible with Locality and Realism would be observed instead. A simple hidden variables model following this hypothesis is described. It is based on a modified Wheeler–Feynman theory of radiation. This hypothesis has not been disproved by any of the experiments performed to date. A test achievable with accessible means is proposed and described. It involves a pulsed source of entangled states and stroboscopic record of particle detection during the pulses. Data recorded in similar but incomplete optical experiments are analyzed, and found consistent with the proposed model. However, it is not claimed, in any sense, that the hypothesis has been validated. On the contrary, it is stressed that a complete, specific test is absolutely needed.

Basic mathematical imputation techniques

2016 ◽  
Vol 61 (9) ◽  
pp. 7-54
Author(s):  
Jacek Wesołowski ◽  
Jakub Tarczyński
Keyword(s):  
Multiple Imputation ◽  
Random Variables ◽  
Independent Random Variables ◽  
Original Sample ◽  
Variance Estimator ◽  
Mathematical Background ◽  
Random Mechanism ◽  
Starting Point

The article presents the basics of imputation methodology (including the methodology of multiple imputation), focusing on understanding its mathematical background. We analyze the situation when observations in the original sample are independent random variables with identical distributions, and response or its lack is modeled by a random mechanism which is independent of observations. In particular, we point out to problems that arise when the standard Rubin estimate of the multiple imputation variance estimator is used. A possible improvement of this popular estimator is indicated. The starting point of the analysis is when the appearance of response deficiencies is caused by a deterministic mechanism.

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

scholarly journals On joint distributions, counterfactual values and hidden variables in understanding contextuality

2019 ◽  
Vol 377 (2157) ◽  
pp. 20190144 ◽  
Author(s):  
Ehtibar N. Dzhafarov
Keyword(s):  
Quantum Mechanics ◽  
Hidden Variables ◽  
Random Variables ◽  
Mathematical Tool ◽  
Theme Issue ◽  
Joint Distributions ◽  
Hidden Variable ◽  
The Core ◽  
Made In

This paper deals with three traditional ways of defining contextuality: (C1) in terms of (non)existence of certain joint distributions involving measurements made in several mutually exclusive contexts; (C2) in terms of relationship between factual measurements in a given context and counterfactual measurements that could be made if one used other contexts; and (C3) in terms of (non)existence of ‘hidden variables’ that determine the outcomes of all factually performed measurements. It is generally believed that the three meanings are equivalent, but the issues involved are not entirely transparent. Thus, arguments have been offered that C2 may have nothing to do with C1, and the traditional formulation of C1 itself encounters difficulties when measurement outcomes in a contextual system are treated as random variables. I show that if C1 is formulated within the framework of the Contextuality-by-Default (CbD) theory, the notion of a probabilistic coupling, the core mathematical tool of CbD, subsumes both counterfactual values and ‘hidden variables’. In the latter case, a coupling itself can be viewed as a maximally parsimonious choice of a hidden variable. This article is part of the theme issue ‘Contextuality and probability in quantum mechanics and beyond’.

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