5,437 research outputs found

    Multidimensional Bosonization

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    Bosonization of degenerate fermions yields insight both into Landau Fermi liquids, and into non-Fermi liquids. We begin our review with a pedagogical introduction to bosonization, emphasizing its applicability in spatial dimensions greater than one. After a brief historical overview, we present the essentials of the method. Well known results of Landau theory are recovered, demonstrating that this new tool of many-body theory is robust. Limits of multidimensional bosonization are tested by considering several examples of non-Fermi liquids, in particular the composite fermion theory of the half-filled Landau level. Nested Fermi surfaces present a different challenge, and these may be relevant in the cuprate superconductors. We conclude by discussing the future of multidimensional bosonization.Comment: 91 pages, 15 eps figures, LaTeX. Minor changes to match the published versio

    Measurement of neutron spectra in liquid hydrogen final report

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    Neutron spectrum measurement in liquid hydrogen and wate

    Working wetlands: classifying wetland potential for agriculture

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    Wetlands / Ecology / Natural resources / Social aspects / Case studies / Zanzibar / Tanzania / Zimbabwe / Swaziland

    An Argument for Indian Status for Native Hawaiians--The Discovery of a Lost Tribe

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    A Case Study of the Environmental Impacts of the Beddown of the C-17 Globemaster III at Charleston AFB

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    Unites States Air Force acquisition environmental planning has changed significantly since the passage of the National Environmental Policy Act in 1969. This research examined the role of environmental planning in weapon system acquisition. It focused on environmental planning performed for the C-17 Globemaster III prior to its beddown at Charleston Air Force Base. The case study of the C- 17 beddown included interviews, archival record reviews, and direct observations at the base. Evidence was collected to determine what environmental impacts occurred during the beddown. An environmental postaudit compared actual impacts with those predicted in environmental planning documentation. Impacts were analyzed to determine if they resulted from local conditions or requirements. A framework of the acquisition process was constructed and environmental requirements were flowcharted. A timeline of C-17 events was developed for comparison of C-17 history with an ideal acquisition process. Finally, environmental planning documentation was evaluated using 20 objective criteria to determine its quality. Two minor impacts were identified at Charleston AFB during data collection in June 1995 - two years after the first C- 17 arrived there. Impacts did not result from unique local conditions. Recommendations were presented regarding the quality and timing of weapon system environmental planning

    Exact Nonperturbative Unitary Amplitudes for 1->N Transitions

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    I present an extension to arbitrary N of a previously proposed field theoretic model, in which unitary amplitudes for 1−>81->8 processes were obtained. The Born amplitude in this extension has the behavior A(1−>N)tree = gN−1 N!A(1->N)^{tree}\ =\ g^{N-1}\ N! expected in a bosonic field theory. Unitarity is violated when ∣A(1−>N)∣>1|A(1->N)|>1, or when N>Ncrit≃e/g.N>\N_crit\simeq e/g. Numerical solutions of the coupled Schr\"odinger equations shows that for weak coupling and a large range of N>\ncrit, the exact unitary amplitude is reasonably fit by a factorized expression |A(1->N)| \sim (0.73 /N) \cdot \exp{(-0.025/\g2)}. The very small size of the coefficient 1/\g2 , indicative of a very weak exponential suppression, is not in accord with standard discussions based on saddle point analysis, which give a coefficient ∼1. \sim 1.\ The weak dependence on NN could have experimental implications in theories where the exponential suppression is weak (as in this model). Non-perturbative contributions to few-point correlation functions in this theory would arise at order $K\ \simeq\ \left((0.05/\g2)+ 2\ ln{N}\right)/ \ ln{(1/\g2)}inanexpansioninpowersof in an expansion in powers of \g2.$Comment: 11 pages, 3 figures (not included

    Hall Effect in the mixed state of moderately clean superconductors

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    The Hall conductivity in the mixed state of a clean (l≫ξ0l \gg \xi_0) type-II s-wave superconductor is determined from a microscopic calculation within a quasiclassical approximation. We find that below the superconducting transition the contribution to the transverse conductivity due to dynamical fluctuations of the order parameter is compensated by the modification of the quasiparticle contribution. In this regime the nonlinear behaviour of the Hall angle is governed by the change in the effective quasiparticle scattering rate due to the reduction in the density of states at the Fermi level. The connection with experimental results is discussed
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