14,134 research outputs found
Hidden assumptions in the derivation of the Theorem of Bell
John Bell's inequalities have already been considered by Boole in 1862. Boole
established a one-to-one correspondence between experimental outcomes and
mathematical abstractions of his probability theory. His abstractions are
two-valued functions that permit the logical operations AND, OR and NOT and are
the elements of an algebra. Violation of the inequalities indicated to Boole an
inconsistency of definition of the abstractions and/or the necessity to revise
the algebra. It is demonstrated in this paper, that a violation of Bell's
inequality by Einstein-Podolsky-Rosen type of experiments can be explained by
Boole's ideas. Violations of Bell's inequality also call for a revision of the
mathematical abstractions and corresponding algebra. It will be shown that this
particular view of Bell's inequalities points toward an incompleteness of
quantum mechanics, rather than to any superluminal propagation or influences at
a distance
Durability testing at 5 atmospheres of advanced catalysts and catalyst supports for gas turbine engine combustors
The durability of CATCOM catalysts and catalyst supports was experimentally demonstrated in a combustion environment under simulated gas turbine engine combustor operating conditions. A test of 1000 hours duration was completed with one catalyst using no. 2 diesel fuel and operating at catalytically-supported thermal combustion conditions. The performance of the catalyst was determined by monitoring emissions throughout the test, and by examining the physical condition of the catalyst core at the conclusion of the test. Tests were performed periodically to determine changes in catalytic activity of the catalyst core. Detailed parametric studies were also run at the beginning and end of the durability test, using no. 2 fuel oil. Initial and final emissions for the 1000 hours test respectively were: unburned hydrocarbons (C3 vppm):0, 146, carbon monoxide (vppm):30, 2420; nitrogen oxides (vppm):5.7, 5.6
Possible Experience: from Boole to Bell
Mainstream interpretations of quantum theory maintain that violations of the
Bell inequalities deny at least either realism or Einstein locality. Here we
investigate the premises of the Bell-type inequalities by returning to earlier
inequalities presented by Boole and the findings of Vorob'ev as related to
these inequalities. These findings together with a space-time generalization of
Boole's elements of logic lead us to a completely transparent Einstein local
counterexample from everyday life that violates certain variations of the Bell
inequalities. We show that the counterexample suggests an interpretation of the
Born rule as a pre-measure of probability that can be transformed into a
Kolmogorov probability measure by certain Einstein local space-time
characterizations of the involved random variables.Comment: Published in: EPL, 87 (2009) 6000
X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2
Measurements of polarization and temperature dependent soft x-ray absorption
have been performed on Na_xCoO_2 single crystals with x=0.4 and x=0.6. They
show a deviation of the local trigonal symmetry of the CoO_6 octahedra, which
is temperature independent in a temperature range between 25 K and 372 K. This
deviation was found to be different for Co^{3+} and Co^{4+} sites. With the
help of a cluster calculation we are able to interpret the Co L_{23}-edge
absorption spectrum and find a doping dependent energy splitting between the
t_{2g} and the e_g levels (10Dq) in Na_xCoO_2.Comment: 7 pages, 8 figure
Initial Stages of Bose-Einstein Condensation
We present the quantum theory for the nucleation of Bose-Einstein
condensation in a dilute atomic Bose gas. This quantum theory comfirms the
results of the semiclassical treatment, but has the important advantage that
both the kinetic and coherent stages of the nucleation process can now be
described in a unified way by a single Fokker-Planck equation.Comment: Four pages of ReVTeX and no figure
KAT-7 Science Verification: Using HI Observations of NGC 3109 to Understand its Kinematics and Mass Distribution
HI observations of the Magellanic-type spiral NGC 3109, obtained with the
seven dish Karoo Array Telescope (KAT-7), are used to analyze its mass
distribution. Our results are compared to what is obtained using VLA data.
KAT-7 is the precursor of the SKA pathfinder MeerKAT, which is under
construction. The short baselines and low system temperature of the telescope
make it sensitive to large scale low surface brightness emission. The new
observations with KAT-7 allow the measurement of the rotation curve of NGC 3109
out to 32', doubling the angular extent of existing measurements. A total HI
mass of 4.6 x 10^8 Msol is derived, 40% more than what was detected by the VLA
observations.
The observationally motivated pseudo-isothermal dark matter (DM) halo model
can reproduce very well the observed rotation curve but the cosmologically
motivated NFW DM model gives a much poorer fit to the data. While having a more
accurate gas distribution has reduced the discrepancy between the observed RC
and the MOdified Newtonian Dynamics (MOND) models, this is done at the expense
of having to use unrealistic mass-to-light ratios for the stellar disk and/or
very large values for the MOND universal constant a0. Different distances or HI
contents cannot reconcile MOND with the observed kinematics, in view of the
small errors on those two quantities. As for many slowly rotating gas-rich
galaxies studied recently, the present result for NGC 3109 continues to pose a
serious challenge to the MOND theory.Comment: 25 pages, 20 figures, accepted for publication in Astronomical
Journa
Superfluidity of spin-polarized 6Li
We study the prospects for observing superfluidity in a spin-polarized atomic
gas of Li atoms, using state-of-the-art interatomic potentials. We
determine the spinodal line and show that a BCS transition to the superfluid
state can indeed occur in the (meta)stable region of the phase diagram if the
densities are sufficiently low. Moreover, for a total density of
, which still fulfills this requirement, we find a critical
temperature of only . We also discuss the stability of the gas due to
exchange and dipolar relaxation and conclude that the prospects for observing
superfluidity in a magnetically trapped atomic Li gas are particularly
promising for magnetic bias fields larger than .Comment: 4 pages of ReVTeX and 2 uuencoded figures. Submitted for publication
in Physical Review Letter
Van Allen Probes show that the inner radiation zone contains no MeV electrons: ECT/MagEIS data
Abstract
We present Van Allen Probe observations of electrons in the inner radiation zone. The measurements were made by the Energetic Particle, Composition, and Thermal Plasma/Magnetic Electron Ion Spectrometer (MagEIS) sensors that were designed to measure electrons with the ability to remove unwanted signals from penetrating protons, providing clean measurements. No electrons \u3e900 keV were observed with equatorial fluxes above background (i.e., \u3e0.1 el/(cm2 s sr keV)) in the inner zone. The observed fluxes are compared to the AE9 model and CRRES observations. Electron fluxes \u3c200 keV exceeded the AE9 model 50% fluxes and were lower than the higher-energy model fluxes. Phase space density radial profiles for 1.3 ≤ L* \u3c 2.5 had mostly positive gradients except near L*~2.1, where the profiles for μ = 20–30 MeV/G were flat or slightly peaked. The major result is that MagEIS data do not show the presence of significant fluxes of MeV electrons in the inner zone while current radiation belt models and previous publications do
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