22,162 research outputs found
Testing Bell's Inequality with Cosmic Photons: Closing the Setting-Independence Loophole
We propose a practical scheme to use photons from causally disconnected
cosmic sources to set the detectors in an experimental test of Bell's
inequality. In current experiments, with settings determined by quantum random
number generators, only a small amount of correlation between detector settings
and local hidden variables, established less than a millisecond before each
experiment, would suffice to mimic the predictions of quantum mechanics. By
setting the detectors using pairs of quasars or patches of the cosmic microwave
background, observed violations of Bell's inequality would require any such
coordination to have existed for billions of years --- an improvement of 20
orders of magnitude.Comment: 5 pages, 4 figures. Minor edits to closely match journal version to
be published in Physical Review Letter
Tungsten wire-reinforced superalloys for 1093 C (2000 F) turbine blade applications
Various combinations of fiber and matrix materials were fabricated and evaluated for the purpose of selecting a specific combination that exhibited the best overall properties for a turbine blade application. A total of seven matrix alloys, including Hastelloy X, Nimonic 80A, Inconel 600, Inconel 625, IN-102, FeCrA1Y, were investigated reinforced with either 218CS tungsten, or W-Hf-C fibers. Based on preliminary screening studies, FeCrA1Y, Inconel 600 and Inconel 625 matrix composites systems were selected for extended thermal cycle tests and for property evaluations which included stress rupture, impact, and oxidation resistance. Of those investigated, the FeCrA1Y matrix composite system exhibited the best overall properties required for a turbine blade application. The W-Hf-C/FeCrA1Y system was selected for further property evaluation. Tensile strength values of up to 724 MPa (105,000 psi) were obtained for this material at 982 C and 607 MPa at 1093 C
Economic Implications of Extraordinary Movements in Stock Prices
macroeconomics, stock market
Interplay between parallel and diagonal electronic nematic phases in interacting systems
An electronic nematic phase can be classified by a spontaneously broken
discrete rotational symmetry of a host lattice. In a square lattice, there are
two distinct nematic phases. The parallel nematic phase breaks and
symmetry, while the diagonal nematic phase breaks the diagonal and
anti-diagonal symmetry. We investigate the interplay between the
parallel and diagonal nematic orders using mean field theory. We found that the
nematic phases compete with each other, while they coexist in a finite window
of parameter space. The quantum critical point between the diagonal nematic and
isotropic phases exists, and its location in a phase diagram depends on the
topology of the Fermi surface. We discuss the implication of our results in the
context of neutron scattering and Raman spectroscopy measurements on
LaSrCuO.Comment: 8 pages, 10 figure
- …