4,114 research outputs found

    Bose Einstein Condensate in a Box

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    Bose-Einstein condensates have been produced in an optical box trap. This novel optical trap type has strong confinement in two directions comparable to that which is possible in an optical lattice, yet produces individual condensates rather than the thousands typical of a lattice. The box trap is integrated with single atom detection capability, paving the way for studies of quantum atom statistics.Comment: 4 pages, 5 figure

    The QGP phase in relativistic heavy-ion collisions

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    The dynamics of partons, hadrons and strings in relativistic nucleus-nucleus collisions is analyzed within the novel Parton-Hadron-String Dynamics (PHSD) transport approach, which is based on a dynamical quasiparticle model for partons (DQPM) matched to reproduce recent lattice-QCD results - including the partonic equation of state - in thermodynamic equilibrium. The transition from partonic to hadronic degrees of freedom is described by covariant transition rates for the fusion of quark-antiquark pairs or three quarks (antiquarks), respectively, obeying flavor current-conservation, color neutrality as well as energy-momentum conservation. The PHSD approach is applied to nucleus-nucleus collisions from low SIS to RHIC energies. The traces of partonic interactions are found in particular in the elliptic flow of hadrons as well as in their transverse mass spectra.Comment: To be published by Springer in Proceedings of the International Symposium on `Exciting Physics', Makutsi-Range, South Africa, 13-20 November, 201

    proton-deuteron elastic scattering above the deuteron breakup

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    The complex Kohn variational principle and the (correlated) hyperspherical harmonics method are applied to study the proton-deuteron elastic scattering at energies above the deuteron breakup threshold. Results for the elastic cross section and various elastic polarization observables have been obtained by fully taking into account the long-range effect of the Coulomb interaction and using a realistic nucleon-nucleon interaction model. Detailed comparison between the theoretical predictions and the accurate and abundant proton-deuteron experimental data can now be performed.Comment: 6 pages, 2 figure

    Quantum Portfolios

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    Quantum computation holds promise for the solution of many intractable problems. However, since many quantum algorithms are stochastic in nature they can only find the solution of hard problems probabilistically. Thus the efficiency of the algorithms has to be characterized both by the expected time to completion {\it and} the associated variance. In order to minimize both the running time and its uncertainty, we show that portfolios of quantum algorithms analogous to those of finance can outperform single algorithms when applied to the NP-complete problems such as 3-SAT.Comment: revision includes additional data and corrects minor typo

    Hydrodynamic modeling of mineral wool fiber suspensions in a two-dimensional flow

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    A consequence of a loss of coolant accident is that the local insulation material is damaged and maybe transported to the containment sump where it can penetrate and/or block the sump strainers. An experimental and theoretical study, which examines the transport of mineral wool fibers via single and multi-effect experiments is being performed. This paper focuses on the experiments and simulations performed for validation of numerical models of sedimentation and resuspension of mineral wool fiber agglomerates in a racetrack type channel. Three velocity conditions are used to test the response of two dispersed phase fiber agglomerates to two drag correlations and to two turbulent dispersion coefficients. The Eulerian multiphase flow model is applied with either one or two dispersed phases

    Emerging Areas of Science: Recommendations for Nursing Science Education from the Council for the Advancement of Nursing Science Idea Festival

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    The Council for the Advancement of Nursing Science aims to “facilitate and recognize life-long nursing science career development” as an important part of its mission. In light of fast-paced advances in science and technology that are inspiring new questions and methods of investigation in the health sciences, the Council for the Advancement of Nursing Science convened the Idea Festival for Nursing Science Education and appointed the Idea Festival Advisory Committee (IFAC) to stimulate dialogue about linking PhD education with a renewed vision for preparation of the next generation of nursing scientists. Building on the 2005 National Research Council report Advancing The Nation\u27s Health Needs and the 2010 American Association of Colleges of Nursing Position Statement on the Research-Focused Doctorate Pathways to Excellence, the IFAC specifically addressed the capacity of PhD programs to prepare nursing scientists to conduct cutting-edge research in the following key emerging and priority areas of health sciences research: omics and the microbiome; health behavior, behavior change, and biobehavioral science; patient-reported outcomes; big data, e-science, and informatics; quantitative sciences; translation science; and health economics. The purpose of this article is to (a) describe IFAC activities, (b) summarize 2014 discussions hosted as part of the Idea Festival, and (c) present IFAC recommendations for incorporating these emerging areas of science and technology into research-focused doctoral programs committed to preparing graduates for lifelong, competitive careers in nursing science. The recommendations address clearer articulation of program focus areas; inclusion of foundational knowledge in emerging areas of science in core courses on nursing science and research methods; faculty composition; prerequisite student knowledge and skills; and in-depth, interdisciplinary training in supporting area of science content and methods

    The Balian-Br\'ezin Method in Relativistic Quantum Mechanics

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    The method suggested by Balian and Br\'ezin for treating angular momentum reduction in the Faddeev equations is shown to be applicable to the relativistic three-body problem.Comment: 14 pages in LaTe

    Reaction-diffusion equations with spatially distributed hysteresis

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    The paper deals with reaction-diffusion equations involving a hysteretic discontinuity in the source term, which is defined at each spatial point. In particular, such problems describe chemical reactions and biological processes in which diffusive and nondiffusive substances interact according to hysteresis law. We find sufficient conditions that guarantee the existence and uniqueness of solutions as well as their continuous dependence on initial data.Comment: 30 pages, 14 figure
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