12,663 research outputs found
Proposed experiments to probe the non-abelian \nu=5/2 quantum Hall state
We propose several experiments to test the non-abelian nature of
quasi-particles in the fractional quantum Hall state of \nu=5/2. One set of
experiments studies interference contribution to back-scattering of current,
and is a simplified version of an experiment suggested recently. Another set
looks at thermodynamic properties of a closed system. Both experiments are only
weakly sensitive to disorder-induced distribution of localized quasi-particles.Comment: Additional references and an improved figure, 5 page
Switching noise as a probe of statistics in the fractional quantum Hall effect
We propose an experiment to probe the unconventional quantum statistics of
quasi-particles in fractional quantum Hall states by measurement of current
noise. The geometry we consider is that of a Hall bar where two quantum point
contacts introduce two interfering amplitudes for back-scattering. Thermal
fluctuations of the number of quasi-particles enclosed between the two point
contacts introduce current noise, which reflects the statistics of the
quasi-particles. We analyze abelian states and the non-abelian
state
Characteristics of a future aeronautical satellite communications system
A possible operational system scenario for providing satellite communications services to the future aviation community was analyzed. The system concept relies on a Ka-band (20/30 GHz) satellite that utilizes multibeam antenna (MBA) technology. The aircraft terminal uses an extremely small aperture antenna as a result of using this higher spectrum at Ka-band. The satellite functions as a relay between the aircraft and the ground stations. The ground stations function as interfaces to the existing terrestrial networks such as the Public Service Telephone Network (PSTN). Various system tradeoffs are first examined to ensure optimized system parameters. High level performance specifications and design approaches are generated for the space, ground, and aeronautical elements in the system. Both technical and economical issues affecting the feasibility of the studied concept are addressed with the 1995 timeframe in mind
Empirical modeling of the quiet time nightside magnetosphere
Empirical modeling of plasma pressure and magnetic field for the quiet time nightside magnetosphere is investigated. Two models are constructed for this study. One model, referred to here as T89R, is basically the magnetic field model of Tsyganenko (1989) but is modified by the addition of an inner eastward ring current at a radial distance of ∼3 RE as suggested by observation. The other is a combination of the T89R model and the long version of the magnetic field model of Tsyganenko (1987) such that the former dominates the magnetic field in the inner magnetosphere, whereas the latter prevails in the distant tail. The distribution of plasma pressure, which is required to balance the magnetic force for each of these two field models, is computed along the tail axis in the midnight meridian. The occurrence of pressure anisotropy in the inner magnetospheric region is also taken into account by determining an empirical fit to the observed plasma pressure anisotropy. This effort is the first attempt to obtain the plasma pressure distribution in force equilibrium with magnetic stresses from an empirical field model with the inclusion of pressure anisotropy. The inclusion of pressure anisotropy alters the plasma pressure by as much as a factor of ∼3 in the inner magnetosphere. The deduced plasma pressure profile along the tail axis is found to be in good agreement with the observed quiet time plasma pressure for geocentric distances between ∼2 and ∼35 RE
Spitzer Constraints on the z=6.56 Galaxy Lensed by Abell 370
We report on Spitzer IRAC observations of the spectroscopically confirmed
z=6.56 lensed Ly-alpha emitting source HCM 6A which was found behind the
cluster Abell 370. Detection of the source at 3.6 and 4.5 microns,
corresponding to rest-frame optical emission, allows us to study the stellar
population of this primeval galaxy. The broadband flux density at 4.5 microns
is enhanced compared to the continuum at other wavelengths, likely due to the
presence of strong H-alpha in emission. The derived H-alpha line flux
corresponds to a star-formation rate of around 140 M_{sun}/yr, more than an
order of magnitude larger than estimates from the ultraviolet continuum and
Ly-alpha emission line. The dust extinction required to explain the discrepancy
is A_V of about 1 mag. The inference of dust at such high redshifts is
surprising and implies that the first epoch of star-formation in this galaxy
occurred at z~20.Comment: 11 pages, 3 figures, ApJ Letters in pres
Juncture stress fields in multicellular shell structures. Volume IV - Stresses and deformations of fixed-edge segmental spherical shells Final report
Equations for thin elastic spherical shells and digital program for analysis of stresses and deformation of fixed edge segmental spherical shells - solution by finite difference techniqu
Property\u27s Constitution
Long-standing disagreements over the definition of property as a matter of legal theory present a special problem in constitutional law. The Due Process and Takings Clauses establish individual rights that can be asserted only if “property” is at stake. Yet the leading cases interpreting constitutional property doctrines have never managed to articulate a coherent general view of property, and in some instances have reached opposite conclusions about its meaning. Most notably, government benefits provided in the form of individual legal entitlements are considered “property” for purposes of due process but not takings doctrines, a conflict the cases acknowledge but do not attempt to explain.
This Article offers a way to bring order to the confused treatment of property in constitutional law. It shows how a single definition of property can be adopted for all of the major constitutional property doctrines without the calamitous results that many seem to fear. The Article begins by arguing that property is best understood as the right to have some measure of legal control over the way a particular item is used, control that comes at the expense of all other people. It then argues that legal rights are a kind of private property, and that while courts and commentators can validly invoke property in the context of legal entitlements to government benefits—so-called new property—they mistakenly believe the property at issue is the good a recipient has a right to receive, rather than the legal right to receive it. The Article shows that legal rights are the only category of things whose existence government can altogether extinguish. For this reason, ownership of legal rights is the only kind of property right government can terminate without conferring equivalent property rights on others. The Article further argues that while due process protection should apply whenever a person is denied an asserted property right (a deprivation), takings protection should only come into play when property rights are transferred from one party to another (a taking). Combining these observations, the Article concludes that termination of both “new property” rights and old-fashioned in personam legal rights should trigger due process but not takings protection. This analysis provides theoretical coherence that constitutional doctrine currently lacks. It also sheds light on the essential characteristics of property rights as a general matter, in order to help theoreticians understand more clearly the core structures of property law
Juncture stress fields in multicellular shell structures. Volume III - Stresses and deformations on fixed-edge segmental conical shells Final report
Equations for thin elastic conical shells and digital program for analysis of stress and deformation on fixed edge segmental conical shells - solution by finite difference techniqu
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