37,044 research outputs found
Third Party Intellectual Property Rights and Contractual Restrictions: Implications for Implementation of the Telecommunica-tions Act of 1996
A General Method for Complete Population Transfer in Degenerate Systems
A simple theoretical solution to the design of a control field that generates
complete population transfer from an initial state, via nondegenerate
intermediate states, to one arbitrary member of () degenerate
states is constructed. The full control field exploits an -node null
adiabatic state, created by designing the relative phases and amplitudes of the
component fields that together make up the full field. The solution found is
universal in the sense that it does not depend on the exact number of the
unwanted degenerate states or their properties. The results obtained suggest
that a class of multi-level quantum systems with degenerate states can be
completely controllable, even under extremely strong constraints, e.g., never
populating a Hilbert subspace that is only a few dimensions smaller than the
whole Hilbert space.Comment: 12 pages, 5 figures, submitted to Phys. Rev.
Dynamics of exploding magma chambers: Implications for K-T volcanism and mass extinctions
Although it is well known that unconfined chemical explosives may yield pressures to several megabars on detonation in air, the explosive literature has yet to be accessed by some contributors to the volcanological literature who've indicated that pressures in excess of the overburden and/or tensile cannot be obtained. Idealized ballistic assessments of pressures internal to volcanoes yield pressures in the hundreds of kilobar range upon correction by addition of friction, etc. Previous assessments of exploding magma chamber pressure have been made from the characteristics of the Mt. St. Helens explosion. A variety of methods yield pressures of similar value: at least hundreds of kilobars. Such results are consistent with free energy requirements for quench supersaturation explosion, a process occurring in solidifying industrial melts. Several reviews of geochemical literature emphasize the carbon event at the Cretaceous-Tertiary (K-T) boundary as being an indicator of a massive dump of CO2 derived from the mantle and entering the atmosphere by extensive global volcanism. Oxygen isotope data indicates extreme warming at the end of the Cretaceous which is consistent with a greenhouse effect attending the CO2 event. Reaction rate equations for the quench supersaturation explosion mechanism indicated, are consistent with the rise in pressure to 30 kbar on solidification of magmatic melts, these pressures limited by the strength of the experimental apparatus
Complete quantum control of the population transfer branching ratio between two degenerate target states
A five-level four-pulse phase-sensitive extended stimulated Raman adiabatic
passage scheme is proposed to realize complete control of the population
transfer branching ratio between two degenerate target states. The control is
achieved via a three-node null eigenstate that can be correlated with an
arbitrary superposition of the target states. Our results suggest that complete
suppression of the yield of one of two degenerate product states, and therefore
absolute selectivity in photochemistry, is achievable and predictable, even
without studying the properties of the unwanted product state beforehand.Comment: 9 pages, 5 figures, to appear in J. Chem. Phy
Low-Income Subsidies for the Medicare Prescription Drug Benefit: The Impact of the Asset Test
Assesses the impact of the requirement that low-income individuals with Medicare meet an asset test in order to receive additional help paying premiums and cost sharing under the new Medicare drug benefit. Raises questions about the equity of the test
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