7,311 research outputs found

    BPS States of Exceptional Non-Critical Strings

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    We study the BPS states of non-critical strings which arise for zero size instantons of exceptional groups. This is accomplished by using F-theory and M-theory duals and by employing mirror symmetry to compute the degeneracy of membranes wrapped around 2-cycles of the Calabi-Yau threefold. We find evidence for a number of novel physical phenomena, including having infinitely many light states with the first lightest state including a nearly massless gravitino.Comment: 29 pages, 1 figure, references added, to appear in the proceedings of the conference "Advanced Quantum Field Theory'' (in memory of Claude Itzykson

    Temporal variations of thermospheric hydrogen derived from in situ measurements

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    Diurnal variations of atomic hydrogen in thermosphere derived from Explorer 32 data and correlated with solar cycle, solar rotation, and earth rotatio

    Thermospheric hydrogen - Absolute densities and temporal variations deduced from in situ measurements

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    Thermospheric model based on Explorer 32 hydrogen ion density measurements including periodic variations and temperature factors due to local time, solar activity, and magnetic effect

    Phase Fluctuations in Strongly Coupled dd-Wave Superconductors

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    We present a numerically exact solution for the BCS Hamiltonian at any temperature, including the degrees of freedom associated with classical phase, as well as amplitude, fluctuations via a Monte Carlo (MC) integration. This allows for an investigation over the whole range of couplings: from weak attraction, as in the well-known BCS limit, to the mainly unexplored strong-coupling regime of pronounced phase fluctuations. In the latter, for the first time two characteristic temperatures T⋆T^\star and TcT_c, associated with short- and long-range ordering, respectively, can easily be identified in a mean-field-motivated Hamiltonian. T⋆T^\star at the same time corresponds to the opening of a gap in the excitation spectrum. Besides introducing a novel procedure to study strongly coupled d-wave superconductors, our results indicate that classical phase fluctuations are not sufficient to explain the pseudo-gap features of high-temperature superconductors (HTS).Comment: 5 pages, 3 figure

    Altitude variation of ion composition in the midlatitude trough region - Evidence for upward plasma flow

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    Altitude effect on ion concentration in midlatitude trough and plasmaspher
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