3,934 research outputs found
Entropy Distance: New Quantum Phenomena
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
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
The Case for Appellate Court Revision
A Review of Rationing Justice on Appeal: The Problems of the U.S. Courts of Appeals by Thomas E. Bake
The Constitution\u27s Second Century - The Shift in Emphasis from Property Rights to Personal Rights
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
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
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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