409 research outputs found

    Unitary nn-designs via random quenches in atomic Hubbard and Spin models: Application to the measurement of R\'enyi entropies

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    We present a general framework for the generation of random unitaries based on random quenches in atomic Hubbard and spin models, forming approximate unitary nn-designs, and their application to the measurement of R\'enyi entropies. We generalize our protocol presented in [Elben2017: arXiv:1709.05060, to appear in Phys. Rev. Lett.] to a broad class of atomic and spin lattice models. We further present an in-depth numerical and analytical study of experimental imperfections, including the effect of decoherence and statistical errors, and discuss connections of our approach with many-body quantum chaos.Comment: This is a new and extended version of the Supplementary material presented in arXiv:1709.05060v1, rewritten as a companion paper. Version accepted to Phys. Rev. A. Minus sign corrected in Eq (5

    Annealing tests of in-pile irradiated oxide coated U–Mo/Al–Si dispersed nuclear fuel

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    Authors do acknowledge the MERARG team for their experimental work (CEA) and F. Charollais, J. Noirot and finally B. Kapusta for their advices and comments. This study was supported by a combined Grant (FRM0911) of the Bundesministerium für Bildung und Forschung (BMBF) and the Bayerisches Staatsministerium für Wissenschaft, Forschung und Kunst (StMWFK).U–Mo/Al based nuclear fuels have been worldwide considered as a promising high density fuel for the conversion of high flux research reactors from highly enriched uranium to lower enrichment. In this paper, we present the annealing test up to 1800°C of in-pile irradiated U–Mo/Al–Si fuel plate samples. More than 70% of the fission gases (FGs) are released during two major FG release peaks around 500°C and 670°C. Additional characterisations of the samples by XRD, EPMA and SEM suggest that up to 500°C FGs are released from IDL/matrix interfaces. The second peak at 670°C representing the main release of FGs originates from the interaction between U–Mo and matrix in the vicinity of the cladding

    Hydrographic station data obtained in the vicinity of Georges Bank, May and August, 1976

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    Two extended cruises were made during May and August, 1976, to measure the regional hydrographic structure in the vicinity of Georges Bank on the New England Continental Shelf. A summary of the hydrographic observations made during Cruise E2B76 on the R/V Eastward and leg 3 of Cruise 13 on the R/V Oceanus are presented in graphic form.Prepared for the United States Geological Survey under Contract No. 14-08-0001-15615 and for· the National Science Foundation under Grant OCE-76-01813 (WHOI)

    Theory of low frequency waves in a rotating stratified channel

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1974.Bibliography: leaf 70.by John A. Vermersch, Jr.M.S

    Sensitivity to the initial state of interacting ultracold bosons in disordered lattices

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    We study the dynamics of a nonlinear one-dimensional disordered system obtained by coupling the Anderson model with the Gross-Pitaevskii equation. An analytical model provides us with a single quantity globally characterizing the localization of the system. This quantity obeys a scaling law with respect to the width of the initial state, which can be used to characterize the dynamics independently of the initial state.Comment: 10 pages, 12 figures, revtex4, submited to PR
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