5,437 research outputs found
Multidimensional Bosonization
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
Neutron spectrum measurement in liquid hydrogen and wate
Working wetlands: classifying wetland potential for agriculture
Wetlands / Ecology / Natural resources / Social aspects / Case studies / Zanzibar / Tanzania / Zimbabwe / Swaziland
A Case Study of the Environmental Impacts of the Beddown of the C-17 Globemaster III at Charleston AFB
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
I present an extension to arbitrary N of a previously proposed field
theoretic model, in which unitary amplitudes for processes were
obtained. The Born amplitude in this extension has the behavior
expected in a bosonic field theory. Unitarity
is violated when , or when 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 The weak dependence
on 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 $K\ \simeq\
\left((0.05/\g2)+ 2\ ln{N}\right)/ \ ln{(1/\g2)}\g2.$Comment: 11 pages, 3 figures (not included
Hall Effect in the mixed state of moderately clean superconductors
The Hall conductivity in the mixed state of a clean () 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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