705 research outputs found
Is Quantum Mechanics Compatible with a Deterministic Universe? Two Interpretations of Quantum Probabilities
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
Weight, volume, and center of mass of segments of human bod
Quantum Holography
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
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
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
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
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?
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
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
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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