Lattice Gauge Theory
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Lattice QCD: a nonperturbative study in the Feynman Gauge / QCD na rede: um estudo não-perturbativo no calibre de Feynman
The infrared behavior of gluon and ghost propagators is of fundamental importance for the understanding of the low-energy limit of quantum chromodynamics (QCD), especially with respect to the problem of the confinement of quarks and gluons. The goal of this thesis is to implement a new method to study the gluon propagator in the linear covariant gauge in lat
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/08/2011
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2. Aspectos não perturbativos das teorias de Yang-Mills no calibre abeliano maximal / Non-perturbative aspects of the Yang-Mills theories in the maximal Albelian gauge
In this, we study the nonperturbative effects associated to the presence of the horizon and to the condensation of local dimension two operators in an Eucledean SU(2)Yang-Mills theory quantized in the maximal Abelian gauge. Such effects are introduced in a way to preserve the properties of renormalizability and locality of the theory. The comparison with the
Publicado em: 2009
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3. Espectro de excitação para modelos de teorias quânticas de campo na rede: modelos puramente fermiônicos e modelos de cromodinâmica quântica / Excitation spectrum for quantum field theory models on the lattice: pure fermionic models and quantum chromodynamics models
In this thesis, we obtain, from a mathematically rigorous point of view, the low-lying energy-momentum spectrum of two $3+1$ dimensional imaginary time lattice quantum filed theory with fermion fields (we give explicit results for the case $d = 3$ and Dirac matrices): a pure fermionic model with quartic interaction in the $N$-component fermion field and a qu
Publicado em: 2008
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4. Propagators, running coupling and condensates in lattice QCD
We present a review of our numerical studies of the running coupling constant, gluon and ghost propagators, ghost-gluon vertex and ghost condensate for the case of pure SU(2) lattice gauge theory in the minimal Landau gauge. Emphasis is given to the infrared regime, in order to investigate the confinement mechanisms of QCD. We compare our results to other th
Brazilian Journal of Physics. Publicado em: 2007-07
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5. The infrared behavior of the gluon and ghost propagators in SU(2) Yang-Mills theory in the maximal abelian gauge
We report on some recent analytical results on the behaviour of the gluon and ghost propagators in Euclidean SU(2) Yang-Mills theory quantized in the maximal Abelian gauge (MAG). This gauge is of particular interest for the dual superconductivity picture to explain color confinement. Two kinds of effects are taken into account: those arising from a treatment
Brazilian Journal of Physics. Publicado em: 2007-07
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6. On the Faddeev-Popov operator eigenspectrum in topological background fields
During the last years significant progress has been made in the understanding of the confinement of quarks and gluons. However, this progress has been made in two directions, which are at first sight very different. On the one hand, topological configurations seem to play an important role in the formation of the static quark-anti-quark potential. On the oth
Brazilian Journal of Physics. Publicado em: 2007-07
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7. On the infrared behavior of Green's functions in Yang-Mills theory
Non-perturbative properties of QCD, such as color confinement, are encoded in the infrared behavior of correlation functions, e.g. propagators and vertices. Various analytic predictions have been suggested for these quantities in various gauges. Here we numerically test these predictions using lattice gauge theory. In particular, we present results for the 2
Brazilian Journal of Physics. Publicado em: 2007-03
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8. Landau gauge gluon and ghost propagators from lattice QCD
We report on recent numerical computations of the Landau gauge gluon and ghost propagators as well as of the ghost-gluon-vertex function in pure SU(3) Yang-Mills theory and in full QCD on the lattice. Special emphasis is paid to the low momentum region. In particular, we present new data for the gluon propagator at momenta below 300 MeV. We also discuss diff
Brazilian Journal of Physics. Publicado em: 2007-03
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9. Connecting an effective model of confinement and chiral symmetry to lattice QCD
We construct an effective model for the chiral field and the Polyakov loop in which we can investigate the interplay between the approximate chiral symmetry restoration and the deconfinement of color in a thermal SU(3) gauge theory with three flavors of massive quarks. The phenomenological couplings between these two sectors can then be related to the recent
Brazilian Journal of Physics. Publicado em: 2007-03
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10. Gribov ambiguities in the maximal Abelian gauge
The effects of the Gribov copies on the gluon and ghost propagators are investigated in SU(2) Euclidean Yang-Mills theory quantized in the maximal Abelian gauge. By following Gribov's original approach, extended to the maximal Abelian gauge, we are able to show that the diagonal component of the gluon propagator displays the characteristic Gribov type behavi
Brazilian Journal of Physics. Publicado em: 2007-03
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11. Estudo numérico da transição de fase na QCD a temperatura finita / Numerical study of QCD phase transition at finite temperature
Em nossas simulações, efetuamos uma cuidadosa análise numérica dos algoritmos de Monte Carlos empregados na termalização de teorias de gauge e sistemas de spins contínuos. Dentre eles, apresentamos uma nova proposta que permite reduzir em cerca de 25% os tempos computacionais. Aplicamos este novo algoritmo ao estudo numérico da transição de desconf
Publicado em: 2005
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12. Gauge theories on the light-front
The light-front quantization of gauge theories in light-cone gauge provides a frame-independent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitary, and a trivial vacuum. The light-front Hamiltonian form of QCD provides an alternative to lattice gauge theory for the computation of nonperturbati
Brazilian Journal of Physics. Publicado em: 2004-03