13,998 research outputs found

    A Rigorous Proof of Fermi Liquid Behavior for Jellium Two-Dimensional Interacting Fermions

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    Using the method of continuous constructive renormalization group around the Fermi surface, it is proved that a jellium two-dimensional interacting system of Fermions at low temperature TT remains analytic in the coupling constant λ\lambda for λlogTK|\lambda| |\log T| \le K where KK is some numerical constant and TT is the temperature. Furthermore in that range of parameters, the first and second derivatives of the self-energy remain bounded, a behavior which is that of Fermi liquids and in particular excludes Luttinger liquid behavior. Our results prove also that in dimension two any transition temperature must be non-perturbative in the coupling constant, a result expected on physical grounds. The proof exploits the specific momentum conservation rules in two dimensions.Comment: 4 pages, no figure

    Interstellar helium in interplanetary space

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    The velocity distribution function of He(+) in the solar wind at 1 AU is calculated with the assumption that the source is photoionization of a cold (T = 100 K), neutral interstellar wind. If the spiral magnetic field is noise free, the velocity distribution is diffuse and would not produce a peak at 4(E over Q) sub H in an E over Q particle spectrum. If the velocity of the interstellar wind with respect to the sun lies in the ecliptic, a large variation of the He(+) number density with respect to ecliptic longitude is expected

    Remarkable virtual SUSY effects in W±W^{\pm} production at high energy hadron colliders

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    We present a complete 1-loop study of the electroweak corrections to the process ugdW+ug\to dW^+ in MSSM and SM. The occurrence of a number of remarkable properties in the behavior of the helicity amplitudes at high energies is stressed, and the crucial role of the virtual SUSY contributions in establishing them, is emphasized. The approach to asymptopia of these amplitudes is discussed, comparing the effects of the logarithmic and constant contributions to the mass suppressed ones, which are relevant at lower energies. Applying crossing to ugdW+ug\to d W^+, we obtain all subprocesses needed for the 1-loop electroweak corrections to W±W^\pm-production at LHC. The SUSY model dependence of such a production is then studied, and illustrations are given for the transverse W±W^{\pm} momentum distribution, as well as the angular distribution in the subprocess center of mass.Comment: 21 pages, 12 figures, version to appear in Phys.Rev.

    Ultralight reactive metal foams produced as structural shapes in space: System design

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    This autonomous experiment for foaming metals in space involved: (1) payload support structure; (2) furnace and foaming apparatus; (3) electronic controls; (4) battery power; and (5) metallurgy. Emphasis was laid on a modular design which was easily modifiable and which offered maximum durability, safety, and failure tolerance

    Fermionic functional renormalization group for first-order phase transitions: a mean-field model

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    First-order phase transitions in many-fermion systems are not detected in the susceptibility analysis of common renormalization-group (RG) approaches. Here we introduce a counterterm technique within the functional renormalization-group (fRG) formalism which allows access to all stable and metastable configurations. It becomes possible to study symmetry-broken states which occur through first-order transitions as well as hysteresis phenomena. For continuous transitions, the standard results are reproduced. As an example, we study discrete-symmetry breaking in a mean-field model for a commensurate charge-density wave. An additional benefit of the approach is that away from the critical temperature for the breaking of discrete symmetries large interactions can be avoided at all RG scales.Comment: 17 pages, 8 figures. v2 corrects typos, adds references and a discussion of the literatur

    A new culture method for biochemical studies of the circadian clock

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    A new culture method for biochemical studies of the circadian cloc

    Screening for female-sterile mutants

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    Screening for female-sterile mutant

    Circadian periodicity in acetate non-utilizing mutants

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    Circadian periodicity in acetate non-utilizing mutant
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