1,299 research outputs found
Why do Bell experiments?
Experiments over three decades have been unable to demonstrate weak
nonlocality in the sense of Bell unambiguously, without loopholes. The last
important loophole remaining is the detection loophole, which is being tackled
by at least three experimental groups. This letter counters five common beliefs
about Bell experiments, and presents alternative scenarios for future
developments.Comment: 10 pages, 1 figure, to be submitted to Natur
Quantum particles from coarse grained classical probabilities in phase space
Quantum particles can be obtained from a classical probability distribution
in phase space by a suitable coarse graining, whereby simultaneous classical
information about position and momentum can be lost. For a suitable time
evolution of the classical probabilities and choice of observables all features
of a quantum particle in a potential follow from classical statistics. This
includes interference, tunneling and the uncertainty relation.Comment: 19 page
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
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Determining Item Screening Criteria Using Cost-Benefit Analysis
Successful testing programs rely on high-quality test items to produce reliable scores and defensible exams. However, determining what statistical screening criteria are most appropriate to support these goals can be daunting. This study describes and demonstrates cost-benefit analysis as an empirical approach to determining appropriate screening criteria for a given testing program and purpose. Using a certification exam’s item pool and simulation we illustrate how to examine a wide range of screening criteria and reach an acceptable balance between the number of items screened out (cost) and pass/fail classification accuracy (benefit). Accessed 699 times on https://pareonline.net from April 09, 2019 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right
Classical probabilities for Majorana and Weyl spinors
We construct a map between the quantum field theory of free Weyl or Majorana
fermions and the probability distribution of a classical statistical ensemble
for Ising spins or discrete bits. More precisely, a Grassmann functional
integral based on a real Grassmann algebra specifies the time evolution of the
real wave function for the Ising states . The time dependent
probability distribution of a generalized Ising model obtains as
. The functional integral employs a lattice
regularization for single Weyl or Majorana spinors. We further introduce the
complex structure characteristic for quantum mechanics. Probability
distributions of the Ising model which correspond to one or many propagating
fermions are discussed explicitly. Expectation values of observables can be
computed equivalently in the classical statistical Ising model or in the
quantum field theory for fermions.Comment: 32 pages, no figure
Entangled qutrits violate local realism stronger than qubits - an analytical proof
In Kaszlikowski [Phys. Rev. Lett. {\bf 85}, 4418 (2000)], it has been shown
numerically that the violation of local realism for two maximally entangled
-dimensional () quantum objects is stronger than for two maximally
entangled qubits and grows with . In this paper we present the analytical
proof of this fact for N=3.Comment: 5 page
expansion of maxillary arches with crossbite a systematic review of rcts in the last 12 years
The aim of this study was to review recent randomized clinical trials (RCTs) dealing with the effectiveness of various modalities of orthopaedic/orthodontic expansion of maxillary arches with crossbite and the associated 6 month post retention stability. The study selection criteria included RCTs involving subjects with maxillary deficiency with crossbite, with no limits of age. The authors searched the following electronic databases from 1999 to January 2011: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, LILACS, and WEB of SCIENCE. The search strategy resulted in 12 articles meeting the inclusion criteria. Most of the studies did not meet major methodological requirements; some studies were not relevant because of small sample size, possible bias and unaccounted for confounding variables, lack of blinding in measurements, and deficient statistical methods. Treatment outcomes were different depending on the appliance used, tooth tissue-borne/tooth-borne expanders, bonded semi-rapid maxillary expansion (SRME), or rapid maxillary expansion (RME); in any case, methodological flaws prevent any sound conclusion. Stable results have been measured at the 6 month follow-up after removal of the retention plate in the treated groups in the maxillary intermolar and intercanine distances. Long-term stability results should be assessed. The Consolidated Standards of Reporting Trials (CONSORT) Statement could be helpful in improving the reporting of RCTs
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