975 resultados para Menno Simons, 1496-1561.
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By introducing an appropriate parent action and considering a perturbative approach, we establish, up to fourth order terms in the field and for the full range of the coupling constant, the equivalence between the non-commutative Yang-Mills-ChernSimons theory and the non-commutative, non-Abelian self-dual model. In doing this, we consider two different approaches by using both the Moyal star-product and the Seiberg-Witten map. (C) 2003 Elsevier B.V. B.V. All rights reserved.
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The addition of a topological Chern-Simons term to three-dimensional higher-derivative gravity is not a good therapy to cure the nonunitarity of the aforementioned theory. Moreover, R+R-2 gravity in (2+1)D, which is unitary at the tree level, becomes tree-level nonunitary when it is augmented by the abovementioned topological term. Therefore, unlike what is claimed in the literature, topological higher-derivative gravity in (2+1)D is not tree-level unitary and neither is topological three-dimensional R+R-2 gravity.
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The use of master actions to prove duality at quantum level becomes cumbersome if one of the dual fields interacts nonlinearly with other fields. This is the case of the theory considered here consisting of U(1) scalar fields coupled to a self-dual field through a linear and a quadratic term in the self-dual field. Integrating perturbatively over the scalar fields and deriving effective actions for the self-dual and the gauge field we are able to consistently neglect awkward extra terms generated via master action and establish quantum duality up to cubic terms in the coupling constant. The duality holds for the partition function and some correlation functions. The absence of ghosts imposes restrictions on the coupling with the scalar fields.
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Quadratic gravity in (2+1)D is nonunitarity at the tree level. When a topological Chern-Simons term is added to this theory, the harmless massive scalar mode of the former gives rise to a troublesome massive spin-0 ghost, while the massive spin-2 ghost is replaced by two massive physical particles both of spin-2. Therefore, unlike what it is claimed in the literature, quadratic Chern-Simons gravity in (2+1)D is nonunitary at the tree level. © 2004 Published by Elsevier B.V.
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Nilpotency of the pure spinor BRST operator in a curved background implies superspace equations of motion for the background. By computing one-loop corrections to nilpotency for the heterotic sigma model, the Yang-Mills Chern-Simons corrections to the background are derived. © 2008 SISSA.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Nesta dissertação obtemos a força de Casimir a temperatura finita entre duas linhas paralelas sujeitas a condição de fronteira do tipo linhas mistas, no contexto da teoria de Maxwell- Chern-Simons em (2+1) dimensões. Além disso, analisamos a simetria de inversão de temperatura apresentada pela energia livre de Helmholtz do modelo para diferentes condições de fronteira. Iniciamos estudando aspectos gerais do formalismo de Matsubara no intuito de introduzirmos efeitos térmicos na teoria; também analisamos aspectos gerais da teoria de MCS em (2 + 1) dimensões. Posteriormente, revisitamos o cálculo da força de Casimir para o caso de duas linhas paralelas infinitamente permeáveis magneticamente a temperatura nula e finita, bem como o caso de linhas mistas a temperatura nula, onde tomamos uma linha perfeitamente condutora eletricamente e outra infinitamente permeável magneticamente. Em seguida, apresentamos novos resultados envolvendo a força de Casimir a temperatura finita com condições de fronteira do tipo linhas mistas. Por último, analisamos a simetria de inversão de temperatura associada a energia livre de Helmholtz do modelo, mostrando que mesmo para condições mistas e possível obter uma espécie de simetria residual, em analogia a resultados existentes para a eletrodinâmica em (3+1) dimensões.
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Pós-graduação em Física - FEG
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Física - IFT
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By computing the two-loop effective potential of the D=3 N=1 supersymmetric Chern-Simons model minimally coupled to a massless self-interacting matter superfield, it is shown that supersymmetry is preserved, while the internal U(1) and the scale symmetries are broken at two-loop order, dynamically generating masses both for the gauge superfield and for the real component of the matter superfield.
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This work is focused on the reconstruction of the intellectual biography of Francesco Platone de' Benedetti, prince of the Bologna's printers (1482-1486), that is the same with his typographical outputs. The research had been divided in two parts: the first, with his life, invesitigated by archive documents, and the second part, focused on the census of his editions, with a particular attention to his types. The research on the typographical types had been developed with Adobe Photoshop, that had allowed me to virtually reconstruct the cases of the Gotic and Roman types used by de' Benedetti.
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La ricerca consiste nell’edizione e traduzione del trattato ‘Practica musice’ di Franchino Gaffurio corredata da apparati critici e storico-contestuali. Si inizia con la biografia dell’autore redatta secondo gli ultimi dati disponibili e si presenta una esposizione del contenuto del trattato con proposte di chiarimenti dei passi più oscuri. Segue quindi uno studio dei cambiamenti intercorsi tra le parti del trattato come trasmesse nei manoscritti preparatori e la sua versione finale a stampa, seguito da una indagine sulle edizioni successive all’editio princeps, con tabelle sulle varianti tra le edizioni. Vengono quindi offerte la trascrizione interpretativa del testo latino del trattato (che può essere considerata la più corretta attualmente disponibile ed è l’unica a riportare numeri di partizione testuale) seguita dalla sua traduzione in italiano, con trascrizione degli esempi musicali. Il trattato, diviso in quattro libri, ha per argomenti rispettivamente il cantus planus e le scale modali gregoriane, la musica misurata e le figure della notazione, l’arte del contrappunto e la più ampia casistica disponibile sulle proporzioni ritmiche.
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Higher gauge theory arises naturally in superstring theory, but many of its features remain obscure. In this thesis, after an exposition of the bacis tools in local higher gauge theory, a higher gauge Chern-Simons model is defined. We discuss the classical equations of motion as well as the behaviour of the gauge anomaly. We perform canonical quantization and we introduce two possible quantization schemes for the model. We also expound higher parallel transport in higher gauge theory, and we speculate that it can provide Wilson surfaces as topological observables for the higher gauge Chern-Simons theory.
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We study Chern-Simons theory on 3-manifolds M that are circle-bundles over 2-dimensional orbifolds Σ by the method of Abelianisation. This method, which completely sidesteps the issue of having to integrate over the moduli space of non-Abelian flat connections, reduces the complete partition function of the non-Abelian theory on M to a 2-dimensional Abelian theory on the orbifold Σ, which is easily evaluated.