Gauge Fields
Mostrando 1-12 de 32 artigos, teses e dissertações.
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1. Natação em espaços curvos via teoria de calibre / A gauge theory approach to the swimming in curved spaces problem
No espaço euclidiano, deformações de corpos quase-rígidos podem gerar rotações globais líquidas que obedecem, em cada instante, a lei de conservação do momento angular (o problema do gato caindo é um exemplo). Em espaços curvos, um ciclo de deformações de um corpo pode gerar não só rotações, mas também translações globais. Este fenômeno
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/05/2010
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2. Is it possible to accommodate massive photons in the framework of a gauge-invariant electrodynamics?
The construction of an alternative electromagnetic theory that preserves Lorentz and gauge symmetries, is considered. We start off by building up Maxwell electrodynamics in (3+1)D from the assumption that the associated Lagrangian is a gauge- invariant functional that depends on the electron and photon fields and their first derivatives only. In this scenari
Brazilian Journal of Physics. Publicado em: 2010-09
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3. Instantons in curved spaces / Instantons em espaços curvos
In this work we study instanton solutions of the Yang-Mills theory in Schwarzschild and Reissner-Nordstrom spaces with gauge group SU(2).Instantons are solutions to the classical field equations of Yang-Mills theory defined in a space with Riemannian (positive de finite)metric with finite action. We begin with a review of the geometric setting of Yang-Mills
Publicado em: 2010
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4. 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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5. Gauge symmetry breaking in the supersymmetric Chern-Simons model / Quebra de simetria de calibre no modelo de Chern-Simons supersimétrico
Através do formalismo de supercampos, estudamos as propriedades ultravioletas da eletrodinâmica quântica supersimétrica no espaço-tempo tridimensional. Mostramos que esta teoria é finita em todas as ordens de perturbação num calibre particular. Também apresentamos uma análise perturbativa do modelo de Chern-Simons supersimétrico acoplado a um supe
Publicado em: 2008
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6. 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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7. 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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8. Equation of state of gluon plasma and renormalization of local action
We consider a local, renormalizable, BRST-invariant action for QCD in Coulomb gauge that contains auxiliary bose and fermi ghost fields. It possess a non-perturbative vacuum that spontaneously breaks BRST-invariance. The vacuum condition leads to a gap equation that introduces a mass scale. Calculations are done to one-loop order in a perturbative expansion
Brazilian Journal of Physics. Publicado em: 2007-03
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9. A local non-Abelian gauge invariant action stemming from the nonlocal operator FmuN(D²)-1FmuN
We report on the nonlocal gauge invariant operator of dimension two, FµN (D²)-1 FµN. We are able to localize this operator by introducing a suitable set of (anti)commuting antisymmetric tensor fields. Starting from this, we succeed in constructing a local gauge invariant action containing a mass parameter, and we prove the renormalizability to all orders
Brazilian Journal of Physics. Publicado em: 2007-03
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10. Campos tensoriais de matÃria abelianos e nÃo-abelianos: geraÃÃo de massa e dualidade. / Abelian and non-abelian tensor matter fields: Mass generation and duality
In this Thesis we analyze the generation of mass to the antisymmetric tensor matter field in a non-Abelian model and the mapping of the antisymmetric matter field to the antisymmetric tensor gauge field in the Abelian case. For the mass generation, we use two different mechanisms. The first one is the spontaneous symmetry breaking, where we use scalar fields
Publicado em: 2007
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11. Tratamento das equações de Eintein-Yang-Mills para soluções numericas com simetria esferica auto-gravitante e simetria axial no espaço-tempo de Minkowski / Set up of Einstein-Yang-Mills equation for numerical solutions of self-gravitating spherical symmetric fields and axial simmetric fields on Minkowski space-time
Nesse trabalho delineamos a teoria clássica para o campo de Einstein-Yang-Mills e elaboramos um conjunto particular de equações para obtermos soluções numéricas. Estudamos dois casos com simetria espaço-temporal: Simetria esférica com campo auto-gravitante e simetria axial no espaço-tempo de Minkowski. Utilizamos métodos numéricos das linhas para
Publicado em: 2007
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12. Comparison of precipitation and incident solar radiation products for South America: observed data and reanalysis / Comparação de produtos de precipitação e radiação solar incidente para a América do Sul: dados observados e reanálises
The goal of this study was to compare nine databases of precipitation and four databases of incident solar radiation of the South America, considering the meridional variation, and the variation across the main continental watersheds (Amazonas, Tocantins, São Francisco, Orinoco, Paraná/Prata, in addition to the main Patagônia basins) and across the main v
Publicado em: 2007