90,900 research outputs found

    Coherent atom-trimer conversion in a repulsive Bose-Einstein condensate

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    We show that the use of a generalized atom-molecule dark state permits the enhanced coherent creation of triatomic molecules in a repulsive atomic Bose-Einstein condensate, with further enhancement being possible in the case of heteronuclear trimers via the constructive interference between two chemical reaction channels.Comment: 3 figure

    Quantum Noise in the Collective Abstraction Reaction A+B 2_2\to AB+B

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    We demonstrate theoretically that the collective abstraction reaction A+B2_2 \to AB+B can be realized efficiently with degenerate bosonic or fermionic matter waves. We show that this is dominated by quantum fluctuations, which are critical in triggering its initial stages with the appearance of macroscopic non-classical correlations of the atomic and molecular fields as a result. This study opens up a promising new regime of quantum degenerate matter-wave chemistry.Comment: 4 pages, 3 figures, publishe

    Probing the SUSY breaking scale at an eee^-e^- collider

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    If supersymmetry is spontaneously at a low energy scale then the resulting gravitino would be very light. The interaction strength of the longitudinal components of such a light gravitino to electron-selectron pair then becomes comparable to that of electroweak interactions. Such a light gravitino could modify the cross-section for e^_L e^_R-->\tilde {e}_L\tilde {e}_R from its MSSM value. Precision measurement of this cross-section could therefore be used to probe the low energy SUSY breaking scale.Comment: Plain Tex, 7 pages, No figure

    Flavor and Spin Contents of the Nucleon in the Quark Model with Chiral Symmetry

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    A simple calculation in the framework of the chiral quark theory of Manohar and Georgi yields results that can account for many of the ''failures'' of the naive quark model: significant strange quark content in the nucleon as indicated by the value of σπN,\sigma _{\pi N}, the u\overline{u}-d\overline{d} asymmetry in the nucleon as measured by the deviation from Gottfried sum rule and by the Drell-Yan process, as well as the various quark contributions to the nucleon spin as measured by the deep inelastic polarized lepton-nucleon scatterings.Comment: figure has been separated from tex file. No other changes. Preprint CMU-HEP94-3

    Safe Concurrency Introduction through Slicing

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    Traditional refactoring is about modifying the structure of existing code without changing its behaviour, but with the aim of making code easier to understand, modify, or reuse. In this paper, we introduce three novel refactorings for retrofitting concurrency to Erlang applications, and demonstrate how the use of program slicing makes the automation of these refactorings possible

    Does being motivated to avoid procedural errors influence their systematicity?

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    Magnetism in 2D BN1x_{1-x}Ox_x and B1x_{1-x}Six_xN: polarized itinerant and local electrons

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    We use density functional theory based first-principles methods to study the magnetism in a 2D hexagonal BN sheet induced by the different concentrations of oxygen and silicon atoms substituting for nitrogen (ON_\mathrm{N}) and boron (SiB_\mathrm{B}) respectively. We demonstrate the possible formation of three distinct phases based on the magnetization energy calculated self-consistently for the ferromagnetic (MEFM_{\mathrm{FM}}) and antiferromagnetic (MEAFM_{\mathrm{AFM}}) states, i.e. the paramagnetic phase with MEFM_{\mathrm{FM}}=MEAFM_{\mathrm{AFM}}, the ferromagnetic phase with MEFM_{\mathrm{FM}}>>MEAFM_{\mathrm{AFM}} and finally the polarized itinerant electrons with finite MEFM_{\mathrm{FM}} but zero MEAFM_{\mathrm{AFM}}. While the ON_\mathrm{N} system was found to exist in all three phases, no tendency towards the formation of the polarized itinerant electrons was observed for the SiB_\mathrm{B} system though the existence of the other two phases was ascertained. The different behavior of these two systems is associated with the diverse features in the magnetization energy as a function of the oxygen and silicon concentrations. Finally, the robustness of the polarized itinerant electron phase is also discussed with respect to the O substitute atom distributions and the applied strains to the system.Comment: accepted by RP
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