21,894 research outputs found

    Meson decay in the Fock-Tani Formalism

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    The Fock-Tani formalism is a first principle method to obtain effective interactions from microscopic Hamiltonians. Usually this formalism was applied to scattering, here we introduced it to calculate partial decay widths for mesons.Comment: Presented at HADRON05 XI. "International Conference on Hadron Spectroscopy" Rio de Janeiro, Brazil, August 21 to 26, 200

    Oxygen clamps in gold nanowires

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    We investigate how the insertion of an oxygen atom in an atomically thin gold nanowire can affect its rupture. We find, using ab initio total energy density functional theory calculations, that O atoms when inserted in gold nanowires form not only stable but also very strong bonds, in such a way that they can extract atoms from a stable tip, serving in this way as a clamp that could be used to pull a string of gold atoms.Comment: 4 pages; 4 figure

    Glueball-glueball scattering in a constituent gluon model

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    In this work we use a mapping technique to derive in the context of a constituent gluon model an effective Hamiltonian that involves explicit gluon degrees of freedom. We study glueballs with two gluons using the Fock-Tani formalism. In the present work we consider two possibilities for 0++0^{++}: (i) as a pure ssˉs\bar{s} and calculate, in the context of a quark interchange picture, the cross-section; (ii) as a glueball where a new calculation for this cross-section is made, in the context of the constituent gluon model, with gluon interchange.Comment: Proceedings of the International Workshop IX Hadron Physics and VII Relativistic Aspects of Nuclear Physics (HADRON-RANP 2004

    Mineralogy of Great Salt Lake: An Analogue for Martian Evaporites

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    Gypsum (CaSO4 · 2H2O) and mirabilite (Na2SO4 · 10H2O) are common precipitates at the Great Salt Lake (GSL). NASA’s Mars Exploration Rover, Opportunity, found veins of gypsum deposited by water in 2011 and gypsum has been detected on Mars as early as 2005 by the ESA’s Mars Express Orbiter. On Earth, gypsum is formed in hypersaline environments, in minerals left behind when water evaporates, trapping microorganisms in fluid inclusions. Likewise, GSL mirabilite develops when mineral-rich groundwater meets cold winter air to create crystalline structures. While there is no physical evidence of mirabilite on Mars, HiRISE Image data show white mounds that some experts hypothesize are related to saline ground waters. Gypsum obtained from Great Salt Lake was used to develop a method to extract halophilic archaea and culture it in the lab. The method obtained could be used to isolate potential microorganisms present in gypsum samples from Mars. Mirabilite is currently under investigation for its ability to enrich halophilic life

    Spin-orbit mode transfer via a classical analog of quantum teleportation

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    We translate the quantum teleportation protocol into a sequence of coherent operations involving three degrees of freedom of a classical laser beam. The protocol, which we demonstrate experimentally, transfers the polarisation state of the input beam to the transverse mode of the output beam. The role of quantum entanglement is played by a non-separable mode describing the path and transverse degrees of freedom. Our protocol illustrates the possibility of new optical applications based on this intriguing classical analogue of quantum entanglement.Comment: 5 pages, 7 figure
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