37,718 research outputs found

    SO(3) Yang-Mills theory on the lattice

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    We numerically investigate the phase structure of pure SO(3) LGT at zero and non-zero temperature in the presence of a Z2 blind monopole chemical potential. The physical meaning of the different phases, a possible symmetry breaking mechanism as well as the existence of an order parameter for the finite temperature phase transition are discussed.Comment: 3 pages, 2 figures LaTeX file. Uses espcrc2 style and amssymb package. Talk given at Lattice2002(nonzerot), Boston. Corrected version with one added referenc

    SO(3) vs. SU(2) Yang-Mills theory on the lattice: an investigation at non-zero temperature

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    The adjoint SU(2) lattice gauge theory in 3+1 dimensions with the Wilson plaquette action modified by a Z(2) monopole suppression term is reinvestigated with special emphasis on the existence of a finite-temperature phase transition decoupling from the well-known bulk transitions.Comment: 13 pages, 9 figures. Based on contributions to CONFINEMENT 2003 and Lattice2003(topology). To be published in Proceedings of CONFINEMENT 2003, Tokyo, Japa

    SAFT-γ Force Field for the Simulation of Molecular Fluids 6. Binary and ternary mixtures comprising water, carbon dioxide, and n-alkanes

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    AbstractThe SAFT-γ coarse graining methodology (Avendaño et al., 2011) is used to develop force fields for the fluid-phase behaviour of binary and ternary mixtures comprising water, carbon dioxide, and n-alkanes. The effective intermolecular interactions between the coarse grained (CG) segments are directly related to macroscopic thermodynamic properties by means of the SAFT-γ equation of state for molecular segments represented with the Mie (generalised Lennard–Jones) intermolecular potential (Papaioannou et al., 2014). The unlike attractive interactions between the components of the mixtures are represented with a single adjustable parameter, which is shown to be transferable over a wide range of conditions. The SAFT-γ Mie CG force fields are used in molecular-dynamics simulations to predict the challenging (vapour+liquid) and (liquid+liquid) fluid-phase equilibria characterising these mixtures, and to study phenomena that are not accessible directly from the equation of state, such as the interfacial properties. The description of the fluid-phase equilibria and interfacial properties predicted with the SAFT-γ Mie force fields is in excellent agreement with the corresponding experimental data, and of comparable if not superior quality to that reported for the more sophisticated atomistic and united-atom models

    Buried heterostructure vertical-cavity surface-emitting laser with semiconductor mirrors

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    We report a buried heterostructure vertical-cavity surface-emitting laser fabricated by epitaxial regrowth over an InGaAs quantum well gain medium. The regrowth technique enables microscale lateral confinement that preserves a high cavity quality factor (loaded Q≈Q\approx 4000) and eliminates parasitic charging effects found in existing approaches. Under optimal spectral overlap between gain medium and cavity mode (achieved here at TT = 40 K) lasing was obtained with an incident optical power as low as PthP_{\rm th} = 10 mW (λp\lambda_{\rm p} = 808 nm). The laser linewidth was found to be ≈\approx3 GHz at Pp≈P_{\rm p}\approx 5 PthP_{\rm th}

    Influência do esterco no crescimento e no acúmulo de nutrientes em mudas de mamão havaí.

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    Analysis of distortion data from TF30-P-3 mixed compression inlet test

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    A program was conducted to reduce and analyze inlet and engine data obtained during testing of a TF30-P-3 engine operating behind a mixed compression inlet. Previously developed distortion analysis techniques were applied to the data to assist in the development of a new distortion methodology. Instantaneous distortion techniques were refined as part of the distortion methodology development. A technique for estimating maximum levels of instantaneous distortion from steady state and average turbulence data was also developed as part of the program

    Jet Modification in a Brick of QGP Matter

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    We have implemented the LPM effect into a microscopic transport model with partonic degrees of freedom by following the algorithm of Zapp & Wiedemann. The Landau-Pomeranchuk-Migdal (LPM) effect is a quantum interference process that modifies the emission of radiation in the presence of a dense medium. In QCD this results in a quadratic length dependence for radiative energy loss. This is an important effect for the modification of jets by their passage through the QGP. We verify the leading parton energy loss in the model against the leading order Baier-Dokshitzer-Mueller-Peigne-Schiff-Zakharov (BDMPS-Z) result. We apply our model to the recent observations of the modification of di-jets at the LHC.Comment: Presented at Panic 1

    LSST optical beam simulator

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    We describe a camera beam simulator for the LSST which is capable of illuminating a 60mm field at f/1.2 with realistic astronomical scenes, enabling studies of CCD astrometric and photometric performance. The goal is to fully simulate LSST observing, in order to characterize charge transport and other features in the thick fully depleted CCDs and to probe low level systematics under realistic conditions. The automated system simulates the centrally obscured LSST beam and sky scenes, including the spectral shape of the night sky. The doubly telecentric design uses a nearly unit magnification design consisting of a spherical mirror, three BK7 lenses, and one beam-splitter window. To achieve the relatively large field the beam-splitter window is used twice. The motivation for this LSST beam test facility was driven by the need to fully characterize a new generation of thick fully-depleted CCDs, and assess their suitability for the broad range of science which is planned for LSST. Due to the fast beam illumination and the thick silicon design [each pixel is 10 microns wide and over 100 microns deep] at long wavelengths there can be effects of photon transport and charge transport in the high purity silicon. The focal surface covers a field more than sufficient for a 40x40 mm LSST CCD. Delivered optical quality meets design goals, with 50% energy within a 5 micron circle. The tests of CCD performance are briefly described.Comment: 9 pages, 9 figure

    Temperature dependence of trapped magnetic field in MgB2 bulk superconductor

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    Based on DC magnetization measurements, the temperature dependencies of the trapped magnetic field have been calculated for two MgB2 samples prepared by two different techniques: the high-pressure sintering and the hot pressing. Experimentally measured trapped field values for the first sample coincide remarkably well with calculated ones in the whole temperature range. This proves, from one side, the validity of the introduced calculation approach, and demonstrates, from another side, the great prospects of the hot pressing technology for large scale superconducting applications of the MgB2.Comment: 3 pages, 3 figures, submitted to AP
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