11,007 research outputs found

    A Meta-Analysis of the Effect of Environmental Contamination and Positive Amenities on Residential Real Estate Values

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    This paper addresses the effects of environmental contamination and positive amenities on proximate residential real estate property values in the United States. Contamination sources include leaking underground storage tanks, superfund sites, landfills, water and air pollution, power lines, pipeline ruptures, nuclear power plants, animal feedlots and several other urban nuisance uses. The study summarizes a literature review of 75 peer-reviewed journal articles and selected case studies, and generates a data set of about 290 observations that contain information about each study’s loss (the dependent variable), with the independent variables being distance from the source, type of contamination, urban or rural environment, geographic region, market conditions and several other variables. Ordinary least squares is used to determine the effect of the contamination variables on reduction in property value. Broad contamination types, amenities, selected economic regions, distance from the source, information, research method and several other variables are statistically significant.

    The Mauna Kea Observatories Near-Infrared Filter Set. I: Defining Optimal 1-5 μ\mum Bandpasses

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    A new MKO-NIR infrared filter set is described, including techniques and considerations given to designing a new set of bandpasses that are useful at both mid- and high-altitude sites. These filters offer improved photometric linearity and in many cases reduced background, as well as preserve good throughput within the JHKLM atmospheric windows. MKO-NIR filters have already been deployed with a number of instruments around the world as part of a filter consortium purchase to reduce the unit cost of filters. Through this effort we hope to establish, for the first time, a single standard set of infrared fitlers at as many observatories as possible.Comment: PASP, in press; 32 pages, 11 figures, 3 Table

    Theory of quantum paraelectrics and the metaelectric transition

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    We present a microscopic model of the quantum paraelectric-ferroelectric phase transition with a focus on the influence of coupled fluctuating phonon modes. These may drive the continuous phase transition first order through a metaelectric transition and furthermore stimulate the emergence of a textured phase that preempts the transition. We discuss two further consequences of fluctuations, firstly for the heat capacity, and secondly we show that the inverse paraelectric susceptibility displays T^2 quantum critical behavior, and can also adopt a characteristic minimum with temperature. Finally, we discuss the observable consequences of our results.Comment: 5 pages, 2 figure

    The Stellar Content Near the Galactic Center

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    High angular resolution J, H, K, and L' images are used to investigate the stellar content within 6 arcsec of SgrA*. The data, which are complete to K ~ 16, are the deepest multicolor observations of the region published to date.Comment: 34 pages, including 12 figure

    A repulsive atomic gas in a harmonic trap on the border of itinerant ferromagnetism

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    Alongside superfluidity, itinerant (Stoner) ferromagnetism remains one of the most well-characterized phases of correlated Fermi systems. A recent experiment has reported the first evidence for novel phase behavior on the repulsive side of the Feshbach resonance in a two-component ultracold Fermi gas. By adapting recent theoretical studies to the atomic trap geometry, we show that an adiabatic ferromagnetic transition would take place at a weaker interaction strength than is observed in experiment. This discrepancy motivates a simple non-equilibrium theory that takes account of the dynamics of magnetic defects and three-body losses. The formalism developed displays good quantitative agreement with experiment.Comment: 4 pages, 2 figure

    Quantum Phase Transitions in Bosonic Heteronuclear Pairing Hamiltonians

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    We explore the phase diagram of two-component bosons with Feshbach resonant pairing interactions in an optical lattice. It has been shown in previous work to exhibit a rich variety of phases and phase transitions, including a paradigmatic Ising quantum phase transition within the second Mott lobe. We discuss the evolution of the phase diagram with system parameters and relate this to the predictions of Landau theory. We extend our exact diagonalization studies of the one-dimensional bosonic Hamiltonian and confirm additional Ising critical exponents for the longitudinal and transverse magnetic susceptibilities within the second Mott lobe. The numerical results for the ground state energy and transverse magnetization are in good agreement with exact solutions of the Ising model in the thermodynamic limit. We also provide details of the low-energy spectrum, as well as density fluctuations and superfluid fractions in the grand canonical ensemble.Comment: 11 pages, 14 figures. To appear in Phys. Rev.

    Feshbach Resonance in Optical Lattices and the Quantum Ising Model

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    Motivated by experiments on heteronuclear Feshbach resonances in Bose mixtures, we investigate s-wave pairing of two species of bosons in an optical lattice. The zero temperature phase diagram supports a rich array of superfluid and Mott phases and a network of quantum critical points. This topology reveals an underlying structure that is succinctly captured by a two-component Landau theory. Within the second Mott lobe we establish a quantum phase transition described by the paradigmatic longitudinal and transverse field Ising model. This is confirmed by exact diagonalization of the 1D bosonic Hamiltonian. We also find this transition in the homonuclear case.Comment: 5 pages, 4 figure

    Tail States in Disordered Superconductors with Magnetic Impurities: the Unitarity Limit

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    When subject to a weak magnetic impurity distribution, the order parameter and quasi-particle energy gap of a weakly disordered bulk s-wave superconductor are suppressed. In the Born scattering limit, recent investigations have shown that `optimal fluctuations' of the random impurity potential can lead to the nucleation of `domains' of localised states within the gap region predicted by the conventional Abrikosov-Gor'kov mean-field theory, rendering the superconducting system gapless at any finite impurity concentration. By implementing a field theoretic scheme tailored to the weakly disordered system, the aim of the present paper is to extend this analysis to the consideration of magnetic impurities in the unitarity scattering limit. This investigation reveals that the qualitative behaviour is maintained while the density of states exhibits a rich structure.Comment: 18 pages AMSLaTeX (with LaTeX2e), 6 eps figure
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