2,276 research outputs found

    A dilemma in representing observables in quantum mechanics

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    There are self-adjoint operators which determine both spectral and semispectral measures. These measures have very different commutativity and covariance properties. This fact poses a serious question on the physical meaning of such a self-adjoint operator and its associated operator measures.Comment: 10 page

    Collective modes and correlations in one-component plasmas

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    The static and time-dependent potential and surface charge correlations in a plasma with a boundary are computed for different shapes of the boundary. The case of a spheroidal or spherical one-component plasma is studied in detail because experimental results are available for such systems. Also, since there is some knowlegde both experimental and theoretical about the electrostatic collective modes of these plasmas, the time-dependent correlations are computed using a method involving these modes.Comment: 20 pages, plain TeX, submitted to Phys. Rev.

    The Pegg-Barnett Formalism and Covariant Phase Observables

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    We compare the Pegg-Barnett (PB) formalism with the covariant phase observable approach to the problem of quantum phase and show that PB-formalism gives essentially the same results as the canonical (covariant) phase observable. We also show that PB-formalism can be extended to cover all covariant phase observables including the covariant phase observable arising from the angle margin of the Husimi Q-function.Comment: 10 page

    Voting on Growth Control Measures: Preferences and Strategies

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    Citizens of many California cities and counties have sought to restrict the rate of population growth in their localities. In 1988, Citizens for Limited Growth used the initiative process to place a pair of growth control measures on the ballot in the City and County of San Diego, respectively. The City Council and Board of Supervisors responded by placing less stringent, competing measures on the same ballot. This paper analyzes voting data from this election to examine the nature of support for such measures. We find strong support for the hypotheses that whites, homeowners, liberal/environmentalists, and those exposed to high levels of traffic congestion are more likely to favor growth controls. This paper also investigates the behavior of voters when they confront competing propositions concerning the same issue on the same ballot, and finds strong evidence of strategic voting

    Static potential in baryon in the method of field correlators

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    The static three-quark potential in arbitrary configuration of quarks is calculated analytically. It is shown to be in a full agreement with the precise numerical simulations in lattice QCD. The results of the work have important application in nuclear physics, as they allow to perform accurate analytic calculations of spectra of the baryons.Comment: 12 pages, 4 eps figures, latex2e, to appear in Yad.Fi

    Absorption in Ultra-Peripheral Nucleus-Atom Collisions in Crystal

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    The Glauber theory description of particle- and nucleus-crystal Coulomb interactions at high-energy is developed. The allowance for the lattice thermal vibrations is shown to produce strong absorption effect which is of prime importance for quantitative understanding of the coherent Coulomb excitation of ultra-relativistic particles and nuclei passing through the crystal.Comment: 8 pages, LaTe

    Static potential in baryon

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    The baryon static potential is calculated in the framework of field correlator method and is shown to match the recent lattice results. The effects of the nonzero value of the gluon correlation length are emphasized.Comment: 7 pages, 4 figures, talk at the NPD-2002 Conference, December 2-6, ITEP, Mosco

    Dynamic Phase Transitions in Cell Spreading

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    We monitored isotropic spreading of mouse embryonic fibroblasts on fibronectin-coated substrates. Cell adhesion area versus time was measured via total internal reflection fluorescence microscopy. Spreading proceeds in well-defined phases. We found a power-law area growth with distinct exponents a_i in three sequential phases, which we denote basal (a_1=0.4+-0.2), continous (a_2=1.6+-0.9) and contractile (a_3=0.3+-0.2) spreading. High resolution differential interference contrast microscopy was used to characterize local membrane dynamics at the spreading front. Fourier power spectra of membrane velocity reveal the sudden development of periodic membrane retractions at the transition from continous to contractile spreading. We propose that the classification of cell spreading into phases with distinct functional characteristics and protein activity patterns serves as a paradigm for a general program of a phase classification of cellular phenotype. Biological variability is drastically reduced when only the corresponding phases are used for comparison across species/different cell lines.Comment: 4 pages, 5 figure
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