578 research outputs found

    Orbital imagery for planetary exploration. Volume 1 - Technical summary

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    Orbital imagery for planetary exploration - objectives, measurements, orbit selection results, and imaging sensor system scaling law

    Orbital imagery for planetary exploration. Volume 2 - Definitions of scientific objectives

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    Orbital imagery for planetary exploration- objective outlines for planetary and atmospheric structure and composition, fields, and extraterrestrial lif

    Prediction of neutron induced activation. Volume 2 - NAP, physical models and experimental validation Final report, May 14, 1964 - Jan. 31, 1966

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    Mathematical models for IBM 7094 computer program prediction of neutron induced activatio

    Orbital imagery for planetary exploration. Volume 4 - Imaging sensor system scaling laws

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    Orbital imagery for planetary exploration - imaging sensor system scaling law

    Prediction of neutron induced activation. Volume I - NAP code manual Final report, May 14, 1964 - Jan. 31, 1966

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    IBM 7094 computer program written in Fortran IV FOR prediction of neutron induced activatio

    Understanding the Random Displacement Model: From Ground-State Properties to Localization

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    We give a detailed survey of results obtained in the most recent half decade which led to a deeper understanding of the random displacement model, a model of a random Schr\"odinger operator which describes the quantum mechanics of an electron in a structurally disordered medium. These results started by identifying configurations which characterize minimal energy, then led to Lifshitz tail bounds on the integrated density of states as well as a Wegner estimate near the spectral minimum, which ultimately resulted in a proof of spectral and dynamical localization at low energy for the multi-dimensional random displacement model.Comment: 31 pages, 7 figures, final version, to appear in Proceedings of "Spectral Days 2010", Santiago, Chile, September 20-24, 201

    The accessible regions presentation of gravity-assisted trajectories using Jupiter

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    Accessibility of solar system regions to earth launched spacecraft using Jupiter gravity- assisted trajectorie

    Low lying spectrum of weak-disorder quantum waveguides

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    We study the low-lying spectrum of the Dirichlet Laplace operator on a randomly wiggled strip. More precisely, our results are formulated in terms of the eigenvalues of finite segment approximations of the infinite waveguide. Under appropriate weak-disorder assumptions we obtain deterministic and probabilistic bounds on the position of the lowest eigenvalue. A Combes-Thomas argument allows us to obtain so-called 'initial length scale decay estimates' at they are used in the proof of spectral localization using the multiscale analysis.Comment: Accepted for publication in Journal of Statistical Physics http://www.springerlink.com/content/0022-471

    Persistence of Anderson localization in Schr\"odinger operators with decaying random potentials

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    We show persistence of both Anderson and dynamical localization in Schr\"odinger operators with non-positive (attractive) random decaying potential. We consider an Anderson-type Schr\"odinger operator with a non-positive ergodic random potential, and multiply the random potential by a decaying envelope function. If the envelope function decays slower than ∣x∣−2|x|^{-2} at infinity, we prove that the operator has infinitely many eigenvalues below zero. For envelopes decaying as ∣x∣−α|x|^{-\alpha} at infinity, we determine the number of bound states below a given energy E<0E<0, asymptotically as α↓0\alpha\downarrow 0. To show that bound states located at the bottom of the spectrum are related to the phenomenon of Anderson localization in the corresponding ergodic model, we prove: (a) these states are exponentially localized with a localization length that is uniform in the decay exponent α\alpha; (b)~ dynamical localization holds uniformly in α\alpha

    New characterizations of the region of complete localization for random Schr\"odinger operators

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    We study the region of complete localization in a class of random operators which includes random Schr\"odinger operators with Anderson-type potentials and classical wave operators in random media, as well as the Anderson tight-binding model. We establish new characterizations or criteria for this region of complete localization, given either by the decay of eigenfunction correlations or by the decay of Fermi projections. (These are necessary and sufficient conditions for the random operator to exhibit complete localization in this energy region.) Using the first type of characterization we prove that in the region of complete localization the random operator has eigenvalues with finite multiplicity
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