705 research outputs found

    Is Quantum Mechanics Compatible with a Deterministic Universe? Two Interpretations of Quantum Probabilities

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    Two problems will be considered: the question of hidden parameters and the problem of Kolmogorovity of quantum probabilities. Both of them will be analyzed from the point of view of two distinct understandings of quantum mechanical probabilities. Our analysis will be focused, as a particular example, on the Aspect-type EPR experiment. It will be shown that the quantum mechanical probabilities appearing in this experiment can be consistently understood as conditional probabilities without any paradoxical consequences. Therefore, nothing implies in the Aspect experiment that quantum theory is incompatible with a deterministic universe.Comment: REVISED VERSION! ONLY SMALL CHANGES IN THE TEXT! compressed and uuencoded postscript, a uuencoded version of a demo program file (epr.exe for DOS) is attached as a "Figure

    Weight, volume, and center of mass of segments of the human body

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    Weight, volume, and center of mass of segments of human bod

    Quantum Holography

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    We propose to make use of quantum entanglement for extracting holographic information about a remote 3-D object in a confined space which light enters, but from which it cannot escape. Light scattered from the object is detected in this confined space entirely without the benefit of spatial resolution. Quantum holography offers this possibility by virtue of the fourth-order quantum coherence inherent in entangled beams.Comment: 7 pages, submitted to Optics Expres

    MGP versus Kochen-Specker condition in hidden variables theories

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    Hidden variables theories for quantum mechanics are usually assumed to satisfy the KS condition. The Bell-Kochen-Specker theorem then shows that these theories are necessarily contextual. But the KS condition can be criticized from an operational viewpoint, which suggests that a weaker condition (MGP) should be adopted in place of it. This leads one to introduce a class of hidden parameters theories in which contextuality can, in principle, be avoided, since the proofs of the Bell-Kochen-Specker theorem break down. A simple model recently provided by the author for an objective interpretation of quantum mechanics can be looked at as a noncontextual hidden parameters theory, which shows that such theories actually exist.Comment: 10 pages, new updated footnotes and quotation

    An experimental test of non-local realism

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    Most working scientists hold fast to the concept of 'realism' - a viewpoint according to which an external reality exists independent of observation. But quantum physics has shattered some of our cornerstone beliefs. According to Bell's theorem, any theory that is based on the joint assumption of realism and locality (meaning that local events cannot be affected by actions in space-like separated regions) is at variance with certain quantum predictions. Experiments with entangled pairs of particles have amply confirmed these quantum predictions, thus rendering local realistic theories untenable. Maintaining realism as a fundamental concept would therefore necessitate the introduction of 'spooky' actions that defy locality. Here we show by both theory and experiment that a broad and rather reasonable class of such non-local realistic theories is incompatible with experimentally observable quantum correlations. In the experiment, we measure previously untested correlations between two entangled photons, and show that these correlations violate an inequality proposed by Leggett for non-local realistic theories. Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned.Comment: Minor corrections to the manuscript, the final inequality and all its conclusions do not change; description of corrections (Corrigendum) added as new Appendix III; Appendix II replaced by a shorter derivatio

    Quantum entanglement and Bell violation of two coupled cavity fields in dissipative environment

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    We study the quantum entanglement between two coupled cavities, in which one is initially prepared in a mesoscopic superposition state and the other is in the vacuum in dissipative environment and show how the entanglement between two cavities can arise in the dissipative environment. The dynamic behavior of the nonlocality for the system is also investigated.Comment: 12 pages, 5 figure

    Entanglement swapping using continuous variables

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    We investigate the efficacy with which entanglement can be teleported using a continuous measurement scheme. We show that by using the correct gain for the classical channel the degree of violation of locality that can be demonstrated (using a CH type inequality) is {\it not} a function of the level of entanglement squeezing used in the teleportation. This is possible because a gain condition can always be choosen such that passage through the teleporter is equivalent to pure attenuation of the input field.Comment: 8 pages, 4 figure

    How much contextuality?

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    The amount of contextuality is quantified in terms of the probability of the necessary violations of noncontextual assignments to counterfactual elements of physical reality.Comment: 5 pages, 3 figure

    PLASMA PROFILE PREDICTION IN NSTX DISCHARGES USING THE UPDATED MULTI-MODE ANOMALOUS TRANSPORT MODULE

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    The objective of this study is twofold: firstly, to demonstrate the consistency between the anomalous transport resultsproduced by updated Multi-Mode Model (MMM) version 9.1 and those obtained through gyrokinetic simulations; andsecondly, to showcase MMM’s ability to predict electron and ion temperature profiles in low aspect ratio, high beta NSTXdischarges. MMM encompasses a range of transport mechanisms driven by electron and ion temperature gradients, trappedelectrons, kinetic ballooning, peeling, microtearing, and drift resistive inertial ballooning modes. These modes within MMMare being verified through corresponding gyrokinetic results. The modes that potentially contribute to ion thermal transport arestable in MMM, aligning with both experimental data and findings from linear CGYRO simulations. The isotope effects onthese modes are also studied and found to be stabilizing, consistent with the experimental trend. The electron thermal poweracross the flux surface is computed within MMM and compared to experimental measurements and nonlinear CGYRO simulationresults. Specifically, the electron temperature gradient modes (ETGM) within MMM account for 2.0 MW of thermalpower, consistent with experimental findings. It is noteworthy that the ETGM model requires approximately 5.0 ms of computationtime on a standard desktop, while nonlinear CGYRO simulations necessitate 8.0 hours on 8 K cores. MMM proves tobe highly computationally efficient, a crucial attribute for various applications, including real-time control, tokamak scenariooptimization, and uncertainty quantification of experimental data

    Violation of Bell inequalities by photons more than 10 km apart

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    A Franson-type test of Bell inequalities by photons 10.9 km apart is presented. Energy-time entangled photon-pairs are measured using two-channel analyzers, leading to a violation of the inequalities by 16 standard deviations without subtracting accidental coincidences. Subtracting them, a 2-photon interference visibility of 95.5% is observed, demonstrating that distances up to 10 km have no significant effect on entanglement. This sets quantum cryptography with photon pairs as a practical competitor to the schemes based on weak pulses.Comment: 4 pages, REVTeX, 2 postscript figures include
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