1,741 research outputs found

    Loop scattering in two-dimensional QCD

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    Using the integrability conditions that we recently obtained in QCD2_2 with massless fermions, we arrive at a sufficient number of conservation laws to be able to fix the scattering amplitudes involving a local version of the Wilson loop operator.Comment: 6 pages, plain tex

    Simulated-tempering approach to spin-glass simulations

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    After developing an appropriate iteration procedure for the determination of the parameters, the method of simulated tempering has been successfully applied to the 2D Ising spin glass. The reduction of the slowing down is comparable to that of the multicanonical algorithm. Simulated tempering has, however, the advantages to allow full vectorization of the programs and to provide the canonical ensemble directly.Comment: 12 pages (LaTeX), 4 postscript figures, uufiles encoded, submitted to Physical Review

    Flat histogram simulation of lattice polymer systems

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    We demonstrate the use of a new algorithm called the Flat Histogram sampling algorithm for the simulation of lattice polymer systems. Thermodynamics properties, such as average energy or entropy and other physical quantities such as end-to-end distance or radius of gyration can be easily calculated using this method. Ground-state energy can also be determined. We also explore the accuracy and limitations of this method. Key words: Monte Carlo algorithms, flat histogram sampling, HP model, lattice polymer systemsComment: 7 RevTeX two-column page

    Gravitation Physics at BGPL

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    We report progress on a program of gravitational physics experiments using cryogenic torsion pendula undergoing large-amplitude torsion oscillation. This program includes tests of the gravitational inverse square law and of the weak equivalence principle. Here we describe our ongoing search for inverse-square-law violation at a strength down to 10510^{-5} of standard gravity. The low-vibration environment provided by the Battelle Gravitation Physics Laboratory (BGPL) is uniquely suited to this study.Comment: To be published in The Proceedings of the Francesco Melchiorri Memorial Conference as a special issue of New Astronomy Review

    QCD Strings as Constrained Grassmannian Sigma Model:

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    We present calculations for the effective action of string world sheet in R3 and R4 utilizing its correspondence with the constrained Grassmannian sigma model. Minimal surfaces describe the dynamics of open strings while harmonic surfaces describe that of closed strings. The one-loop effective action for these are calculated with instanton and anti-instanton background, reprsenting N-string interactions at the tree level. The effective action is found to be the partition function of a classical modified Coulomb gas in the confining phase, with a dynamically generated mass gap.Comment: 22 pages, Preprint: SFU HEP-116-9

    An Analysis of Four-quark Energies in SU(2) Lattice Monte Carlo using the Flux-tube Symmetry:

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    Energies of four-quark systems calculated by the static quenched SU(2) lattice Monte Carlo method are analyzed in 2×22\times 2 bases for square, rectangle, tilted rectangle, linear and quadrilateral geometry configurations and in 3×33\times 3 bases for a non-planar geometry configuration. For small interquark distances, a lattice effect is taken into account by considering perimeter dependent terms which are characterized by the cubic symmetry. It is then found that a parameter ff - that can be identified as a gluon field overlap factor - is rather well described by the form exp([bsEA+bsFP])exp(-[b_sE{\cal A}+\sqrt{b_s}F{\cal P}]), where A{\cal A} and P{\cal P} are the area and perimeter mainly defined by the positions of the four quarks, bsb_s is the string constant in the 2-quark potentials and E,FE,F are constants.Comment: (19 pages of Latex - 1 page of figures not included - sent on request). Preprint HU-TFT-94-2

    Instanton size distribution in O(3)

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    We present calculations of the size distribution of instantons in the 2d O(3) non-linear sigma-model, and briefly discuss the effects cooling has upon the configurations and the topological objects. (This preprint is also available via anonymous ftp to suna.amtp.liv.ac.uk in /pub/pss/ as instdist.uue.)Comment: 17 pages, LaTeX, needs cite.sty (appended), with appended uuencoded compressed tarfile of PostScript figures, Liverpool preprint LTH-33
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