3,925 research outputs found

    Entropy Distance: New Quantum Phenomena

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    We study a curve of Gibbsian families of complex 3x3-matrices and point out new features, absent in commutative finite-dimensional algebras: a discontinuous maximum-entropy inference, a discontinuous entropy distance and non-exposed faces of the mean value set. We analyze these problems from various aspects including convex geometry, topology and information geometry. This research is motivated by a theory of info-max principles, where we contribute by computing first order optimality conditions of the entropy distance.Comment: 34 pages, 5 figure

    Cryogenic scanning force microscopy of quantum Hall samples: Adiabatic transport originating in anisotropic depletion at contact interfaces

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    Anisotropic magneto resistances and intrinsic adiabatic transport features are generated on quantum Hall samples based on an (Al,Ga)As/GaAs heterostructure with alloyed Au/Ge/Ni contacts. We succeed to probe the microscopic origin of these transport features with a cryogenic scanning force microscope (SFM) by measuring the local potential distribution within the two-dimensional electron system (2DES). These local measurements reveal the presence of an incompressible strip in front of contacts with insulating properties depending on the orientation of the contact/2DES interface line relatively to the crystal axes of the heterostructure. Such an observation gives another microscopic meaning to the term 'non-ideal contact' used in context with the Landauer-B\"uttiker formalism applied to the quantum Hall effect.Comment: 5 pages, 4 figure

    Are Courts Obsolete

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    The Case for Appellate Court Revision

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    A Review of Rationing Justice on Appeal: The Problems of the U.S. Courts of Appeals by Thomas E. Bake

    Austin L. Staley

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    The Constitution\u27s Second Century - The Shift in Emphasis from Property Rights to Personal Rights

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    We celebrate the two hundredth anniversary of the Constitution this year confident that it will survive for at least another hundred years. As is true of many things American, the observance of the occasion has devoted more than enough attention to the historic days of 1787 when the document was drafted. The Constitution of today, in reality, consists not only of the original text but of significant court decisions over the years. To gain some understanding of what is meant by constitutional rights today requires a review of some of the important cases. The focus here is on the shift from the courts\u27 early emphasis on property rights to the later attention to what might be called personal rights and is largely a historical and chronological review rather than a philosophical one

    Structure formation in binary colloids

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    A theoretical study of the structure formation observed very recently [Phys. Rev. Lett. 90, 128303 (2003)] in binary colloids is presented. In our model solely the dipole-dipole interaction of the particles is considered, electrohidrodynamic effects are excluded. Based on molecular dynamics simulations and analytic calculations we show that the total concentration of the particles, the relative concentration and the relative dipole moment of the components determine the structure of the colloid. At low concentrations the kinetic aggregation of particles results in fractal structures which show a crossover behavior when increasing the concentration. At high concentration various lattice structures are obtained in a good agreement with experiments.Comment: revtex, 4 pages, figures available from authors due to size problem

    A spectral and spatial analysis of eta Carinae's diffuse X-ray emission using CHANDRA

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    The luminous unstable star (star system) eta Carinae is surrounded by an optically bright bipolar nebula, the Homunculus and a fainter but much larger nebula, the so-called outer ejecta. As images from the EINSTEIN and ROSAT satellites have shown, the outer ejecta is also visible in soft X-rays, while the central source is present in the harder X-ray bands. With our CHANDRA observations we show that the morphology and properties of the X-ray nebula are the result of shocks from fast clumps in the outer ejecta moving into a pre-existing denser circumstellar medium. An additional contribution to the soft X-ray flux results from mutual interactions of clumps within the ejecta. Spectra extracted from the CHANDRA data yield gas temperatures kT of 0.6-0.76 keV. The implied pre-shock velocities of 670-760 km/s are within the scatter of the velocities we measure for the majority of the clumps in the corresponding regions. Significant nitrogen enhancements over solar abundances are needed for acceptable fits in all parts of the outer ejecta, consistent with CNO processed material and non-uniform enhancement. The presence of a diffuse spot of hard X-ray emission at the S condensation shows some contribution of the highest velocity clumps and further underlines the multicomponent, non-equilibrium nature of the X-ray nebula. The detection of an X-ray ``bridge'' between the northern and southern part of the X-ray nebula and an X-ray shadow at the position of the NN bow can be attributed to a large expanding disk, which would appear as an extension of the equatorial disk. No soft emission is seen from the Homunculus, or from the NN bow or the ``strings''.Comment: 15 pages, 10 figures, accepted by A&A; paper including images with full resolution available at http://www.astro.ruhr-uni-bochum.de/kweis/publications.htm
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