25,105 research outputs found

    Screening in (2+1)D pure gauge theory at high temperatures

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    We compute heavy quark potentials in pure gauge SU(3)SU(3) at high temperatures in 2+12+1 dimensions and confront them with expectations emerging from perturbative calculations.Comment: 3 pages, latex, 4 figures, uu, Contribution to LATTICE 9

    Spectroscopy of a synthetic trapped ion qubit

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    133Ba+^{133}\text{Ba}^+ has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1/2 nucleus and visible wavelength electronic transitions. Using a microgram source of radioactive material, we trap and laser-cool the synthetic AA = 133 radioisotope of barium II in a radio-frequency ion trap. Using the same, single trapped atom, we measure the isotope shifts and hyperfine structure of the 62P1/26^2 \text{P}_{1/2} ↔\leftrightarrow 62S1/26^2 \text{S}_{1/2} and 62P1/26^2 \text{P}_{1/2} ↔\leftrightarrow 52D3/25^2 \text{D}_{3/2} electronic transitions that are needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. We also report the 62P1/26^2 \text{P}_{1/2} ↔\leftrightarrow 52D3/25^2 \text{D}_{3/2} electronic transition isotope shift for the rare AA = 130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes

    Numerical indications on the semiclassical limit of the flipped vertex

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    We introduce a technique for testing the semiclassical limit of a quantum gravity vertex amplitude. The technique is based on the propagation of a semiclassical wave packet. We apply this technique to the newly introduced "flipped" vertex in loop quantum gravity, in order to test the intertwiner dependence of the vertex. Under some drastic simplifications, we find very preliminary, but surprisingly good numerical evidence for the correct classical limit.Comment: 4 pages, 8 figure

    Planetary/DOD entry technology flight experiments. Volume 3: Planetary entry flight experiments handbook

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    The environments produced by entry into Jupiter and Saturn atmospheres are summarized. Worst case design environments are identified and the effect of entry angle, type of atmosphere and ballistic coefficient variations are presented. The range of environments experienced during earth entry is parametrically described as a function of initial entry conditions. The sensitivity of these environments to vehicle ballistic coefficient and nose radius is also shown. An elliptical deorbit maneuver strategy is defined in terms of the velocity increment required versus initial entry conditions and apoapsis altitude. Mission time, ground track, and out of plane velocity penalties are also presented. Performance capabilities of typical shuttle launched boosters are described including the initial entry conditions attainable as a function of paylaod mass and apoapsis altitude

    Planetary/DOD entry technology flight experiments. Volume 1: Executive summary

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    The feasibility of using the space shuttle to launch planetary and DoD entry flight experiments was examined. The results of the program are presented in two parts: (1) simulating outer planet environments during an earth entry test, the prediction of Jovian and earth radiative heating dominated environments, mission strategy, booster performance and entry vehicle design, and (2) the DoD entry test needs for the 1980's, the use of the space shuttle to meet these DoD test needs, modifications of test procedures as pertaining to the space shuttle, modifications to the space shuttle to accommodate DoD test missions and the unique capabilities of the space shuttle. The major findings of this program are summarized

    The Electronic Correlation Strength of Pu

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    An electronic quantity, the correlation strength, is defined as a necessary step for understanding the properties and trends in strongly correlated electronic materials. As a test case, this is applied to the different phases of elemental Pu. Within the GW approximation we have surprisingly found a "universal" scaling relationship, where the f-electron bandwidth reduction due to correlation effects is shown to depend only on the local density approximation bandwidth and is otherwise independent of crystal structure and lattice constant.Comment: 7 pages, 4 figures, This version of the paper has been revised to add additional background informatio
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