3,942 research outputs found

    Simpler proof of the theorem by Pusey, Barrett, and Rudolph on the reality of the quantum state

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    The theorem of Pusey, Barrett, and Rudolph proves that different quantum states describe different physical realities. Their proof is based on the construction of entanglement measurement bases of two, and more than two qbits. In this note, I show that a two-qubit entanglement base is sufficient for a general proof.Comment: 5 pages, 2 figure

    N-component Bose-Einstein Condensate in an Optical Lattice: Destruction of the Condensate and Quasiparticle Properties

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    We present a model of N-component hard-core bosons on a lattice. The limit N to infinity can be solved exactly. A saddle point approximation leads to a 1/N expansion and allows the calculation of physical quantities like the density of the condensate, the correlation between the components and the density-density correlation function and the correlation between different components. We find a superfluid phase with a tendency towards a Mott insulator at high densities and finite N.Comment: 8 pages, 3 figures, small changes, error corrected in Appendi

    Life sciences Spacelab Mission Development test 3 (SMD 3) data management report

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    Development of a permanent data system for SMD tests was studied that would simulate all elements of the shuttle onboard, telemetry, and ground data systems that are involved with spacelab operations. The onboard data system (ODS) and the ground data system (GDS) were utilized. The air-to-ground link was simulated by a hardwired computer-to-computer interface. A patch board system was used on board to select experiment inputs, and the downlink configuration from the ODS was changed by a crew keyboard entry to support each experiment. The ODS provided a CRT display of experiment parameters to enable the crew to monitor experiment performance. An onboard analog system, with recording capability, was installed to handle high rate data and to provide a backup to the digital system. The GDS accomplished engineering unit conversion and limit sensing, and provided realtime parameter display on CRT's in the science monitoring area and the test control area

    A brief description of the Medical Information Computer System (MEDICS)

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    The Medical Information Computer System (MEDICS) is a time shared, disk oriented minicomputer system capable of meeting storage and retrieval needs for the space- or non-space-related applications of at least 16 simultaneous users. At the various commercially available low cost terminals, the simple command and control mechanism and the generalized communication activity of the system permit multiple form inputs, real-time updating, and instantaneous retrieval capability with a full range of options

    Aerodynamic characteristics determined during development of the Apollo launch escape vehicle configuration

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    Aerodynamic characteristics determined during development of Apollo launch escape vehicle configuration in wind tunnel test

    Aerodynamic loads on deployed canard surfaces and rocket nose section of the Apollo launch escape vehicle

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    Aerodynamic loads on deployed canard surfaces and rocket nose section of Apollo launch escape vehicl

    Wind-tunnel investigation of the aerodynamic pressures on the Apollo command module configuration

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    Wind tunnel study of aerodynamic pressures on Apollo command module configuratio

    Dynamical Mean Field Theory for the Bose-Hubbard Model

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    The dynamical mean field theory (DMFT), which is successful in the study of strongly correlated fermions, was recently extended to boson systems [Phys. Rev. B {\textbf 77}, 235106 (2008)]. In this paper, we employ the bosonic DMFT to study the Bose-Hubbard model which describes on-site interacting bosons in a lattice. Using exact diagonalization as the impurity solver, we get the DMFT solutions for the Green's function, the occupation density, as well as the condensate fraction on a Bethe lattice. Various phases are identified: the Mott insulator, the Bose-Einstein condensed (BEC) phase, and the normal phase. At finite temperatures, we obtain the crossover between the Mott-like regime and the normal phase, as well as the BEC-to-normal phase transition. Phase diagrams on the μ/U−t~/U\mu/U-\tilde{t}/U plane and on the T/U−t~/UT/U-\tilde{t}/U plane are produced (t~\tilde{t} is the scaled hopping amplitude). We compare our results with the previous ones, and discuss the implication of these results to experiments.Comment: 11 pages, 8 figure

    Interacting bosons in an optical lattice: Bose-Einstein condensates and Mott insulator

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    A dense Bose gas with hard-core interaction is considered in an optical lattice. We study the phase diagram in terms of a special mean-field theory that describes a Bose-Einstein condensate and a Mott insulator with a single particle per lattice site for zero as well as for non-zero temperatures. We calculate the densities, the excitation spectrum and the static structure factor for each of these phases.Comment: 17 pages, 5 figures; 1 figure added, typos remove
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