3,947 research outputs found
Application of DInSAR-GPS optimization for derivation of fine-scale surface motion maps of Southern California
A method based on random field theory and Gibbs-Markov random fields equivalency within Bayesian statistical framework is used to derive 3-D surface motion maps from sparse global positioning system (GPS) measurements and differential interferometric synthetic aperture radar (DInSAR) interferogram in the southern California region. The minimization of the Gibbs energy function is performed analytically, which is possible in the case when neighboring pixels are considered independent. The problem is well posed and the solution is unique and stable and not biased by the continuity condition. The technique produces a 3-D field containing estimates of surface motion on the spatial scale of the DInSAR image, over a given time period, complete with error estimates. Significant improvement in the accuracy of the vertical component and moderate improvement in the accuracy of the horizontal components of velocity are achieved in comparison with the GPS data alone. The method can be expanded to account for other available data sets, such as additional interferograms, lidar, or leveling data, in order to achieve even higher accuracy
Two-loop low-energy effective action in Abelian supersymmetric Chern-Simons matter models
We compute two-loop low-energy effective actions in Abelian Chern-Simons
matter models with N=2 and N=3 supersymmetry up to four-derivative order.
Calculations are performed with a slowly-varying gauge superfield background.
Though the gauge superfield propagator depends on the gauge fixing parameter,
it is shown that the obtained results are independent of this parameter. In the
massless case the considered models are superconformal. We demonstrate that the
superconformal symmetry strongly restricts the form of two-loop quantum
corrections to the effective actions such that the obtained terms have simpler
structure than the analogous ones in the effective action of three-dimensional
supersymmetric electrodynamics (SQED) with vanishing topological mass.Comment: 1+30 pages; v2: references added, misprints corrected; v3: minor
changes, published versio
Vapor pressure and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures
The vapor pressure and evaporation rate of borides of titanium, zirconium, and chrome; and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide; and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum
SUSY transformations with complex factorization constants. Application to spectral singularities
Supersymmetric (SUSY) transformation operators corresponding to complex
factorization constants are analyzed as operators acting in the Hilbert space
of functions square integrable on the positive semiaxis. Obtained results are
applied to Hamiltonians possessing spectral singularities which are
non-Hermitian SUSY partners of selfadjoint operators. A new regularization
procedure for the resolution of the identity operator in terms of continuous
biorthonormal set of the non-Hermitian Hamiltonian eigenfunctions is proposed.
It is also shown that the continuous spectrum eigenfunction has zero binorm (in
the sense of distributions) at the singular point.Comment: Thanks to A. Sokolov a number of inaccuracies are correcte
Galactic cosmic ray currents and magnetic field irregularity degree in high-speed solar wind streams
Currents of galactic cosmic rays (GCR) obtained by global survey method are analyzed. The cases of almost total disappearance of GCR currents are compared with the results of direct measurements of the solar wind parameters. The conclusion is made on a restricted application of the convective-diffusive mechanism of the GCR modulation by the solar wind during the occurrence of stationary and regular magnetic fields in the interplanetary medium
Sums of nearly Kähler f-structures on homogeneous Ф-spaces of order k
In this article, we indicate appropriate necessary and sufficient conditions for a sum of three base canonical f–structures on homogeneous Ф-spaces of order k to be an NKf-structure and describe some special cases of the theorem
Minimum error discrimination problem for pure qubit states
The necessary and sufficient conditions for minimization of the generalized
rate error for discriminating among pure qubit states are reformulated in
terms of Bloch vectors representing the states. For the direct optimization
problem an algorithmic solution to these conditions is indicated. A solution to
the inverse optimization problem is given. General results are widely
illustrated by particular cases of equiprobable states and pure qubit
states given with different prior probabilities.Comment: English is corrected thanks to PRA edito
Three-dimensional structure of Mach cones in monolayer complex plasma
Structure of Mach cones in a crystalline complex plasma has been studied
experimentally using an intensity sensitive imaging, which resolved particle
motion in three dimensions. This revealed a previously unknown out-of-plane
cone structure, which appeared due to excitation of the vertical wave mode. The
complex plasma consisted of micron sized particles forming a monolayer in a
plasma sheath of a gas discharge. Fast particles, spontaneously moving under
the monolayer, created Mach cones with multiple structures. The in-plane cone
structure was due to compressional and shear lattice waves.Comment: Accepted for publication in Physical Review Letter
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