11,282 research outputs found
Correlation effects in the density of states of annealed GaMnAs
We report on an experimental study of low temperature tunnelling in hybrid
NbTiN/GaMnAs structures. The conductance measurements display a root mean
square V dependence, consistent with the opening of a correlation gap in the
density of states of GaMnAs. Our experiment shows that low temperature
annealing is a direct empirical tool that modifies the correlation gap and thus
the electron-electron interaction. Consistent with previous results on
boron-doped silicon we find, as a function of voltage, a transition across the
phase boundary delimiting the direct and exchange correlation regime.Comment: Replaced with revised version. To appear in Phys. Rev.
Synthesis of finite displacements and displacements in continental margins
The scope of the project is the analysis of displacement-rate fields in the transitional regions between cratonal and oceanic lithospheres over Phanerozoic time (last 700 ma). Associated goals are an improved understanding of range of widths of major displacement zones; the partition of displacement gradients and rotations with position and depth in such zones; the temporal characteristics of such zones-the steadiness, episodicity, and duration of uniform versus nonunifrom fields; and the mechanisms and controls of the establishment and kinematics of displacement zones. The objective is to provide a context of time-averaged kinematics of displacement zones. The initial phase is divided topically among the methodology of measurement and reduction of displacements in the lithosphere and the preliminary analysis from geologic and other data of actual displacement histories from the Cordillera, Appalachians, and southern North America
Universality and Scaling at the Onset of Quantum Black Hole Formation
In certain two-dimensional models, collapsing matter forms a black hole if
and only if the incoming energy flux exceeds the Hawking radiation rate. Near
the critical threshold, the black hole mass is given by a universal formula in
terms of the distance from criticality, and there exists a scaling solution
describing the formation and evaporation of an arbitrarily small black hole.Comment: 9 pages, 3 figures (uuencoded
Supermarket Dairy Department: An Overview of Operations and Performance
A.E. Ext. 91-18The'objective of this report is to provide an overview of supermarket dairy department operations and a statistical profile of its performance. Major trends and key operating data for the dairy department are identified and interpreted, especially relative to similar benchmarks in other departm.ents in the supermarket. The information drawn upon to make these assessments has been compiled from a variety of secondary sources. The specific industry resources and academic research reports are listed in the References
Initial singularity free quantum cosmology in two-dimensional Brans-Dicke theory
We consider two-dimensional Brans-Dicke theory to study the initial
singularity problem. It turns out that the initial curvature singularity can be
finite for a certain Brans-Dicke constant by considering the quantum
back reaction of the geometry. For , the universe starts with the
finite curvature scalar and evolves into the flat spacetime. Furthermore the
divergent gravitational coupling at the initial time can be finite effectively
with the help of quantum correction. The other type of universe is studied for
the case of .Comment: 12 pages, 4 figures, revtex, Some references are added. To be
published in Phys. Rev.
Filtered integration rules for finite weighted Hilbert transforms
A product quadrature rule, based on the filtered de la VallĂ©e Poussin polynomial approximation, is proposed for evaluating the finite weighted Hilbert transform in [â1,1]. Convergence results are stated in weighted uniform norm for functions belonging to suitable Besov-type subspaces. Several numerical tests are provided, also comparing the rule with other formulas known in literature
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