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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Super Yang-Mills theories on the lattice

Bibireata, Daniel, January 2005 (has links)
Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains x, 94 p.; also includes graphics Includes bibliographical references (p. 52-54). Available online via OhioLINK's ETD Center
62

Phase structure of maximally supersymmetric Yang-Mills theory with R-symmetry chemical potentials /

Yamada, Daisuke. January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 65-70).
63

Two dimensional supersymmetric models and some of their thermodynamic properties from the context of SDLCQ

Proestos, Yiannis, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 190-199).
64

Nichtperturbative Untersuchungen der SU(2) Yang-Mills-Theorie in 2+1 Dimensionen

Häuser, Jörn Matthias. Unknown Date (has links)
Universiẗat, Diss., 1997--Gießen.
65

Application of many body techniques to canonically quantized Yang-Mills theories

Schröder, Oliver. Unknown Date (has links) (PDF)
University, Diss., 2002--Tübingen.
66

Modern perturbative techniques applied to Yang-Mills and gravity theories

Alston, Sam D. January 2013 (has links)
No description available.
67

Large R-charge operators in N =4 super Yang-Mills and their gravity duals

Ives, Norman 16 September 2011 (has links)
Ph.D., Faculty of Science, University of Witwatersrand, 2011 / Operators in N = 4 super Yang-Mills theory with an R-charge of O(N2) are dual to backgrounds which are asymtotically AdS5 S5. In this thesis we develop e cient techniques that allow the computation of correlation functions in these backgrounds. We nd that (i) contractions between elds in the string words and elds in the operator creating the background are the eld theory accounting of the new geometry, (ii) correlation functions of probes in these backgrounds are given by the free eld theory contractions but with rescaled propagators and (iii) in these backgrounds there are no open string excitations with their special end point interactions; we have only closed string excitations. Furthermore, these correlation functions are not well approximated by the planar limit. The non-planar diagrams, which in the bulk spacetime correspond to string loop corrections, are enhanced by huge combinatorial factors. We show how these loop corrections can be resummed. As a typical example of our results, in the half-BPS background of M maximal giant gravitons we nd the usual 1=N expansion is replaced by a 1=(M +N) expansion. Further, we nd that there is a simple exact relationship between amplitudes computed in the trivial background and amplitudes computed in the background of M maximal giant gravitons. We also nd strong evidence for the BMN-type sectors suggested in arXiv:0801.4457. The problem of computing the anomalous dimensions of (nearly) half-BPS operators with a large R-charge is reduced to the problem of diagonalizing a Cuntz oscillator chain. Due to the large dimension of the operators we consider, non-planar corrections must be summed to correctly construct the Cuntz oscillator dynamics. These non-planar corrections do not represent quantum corrections in the dual gravitational theory, but rather, they account for the backreaction from the heavy operator whose dimension we study. Non-planar corrections accounting for quantum corrections seem to spoil integrability, in general. It is interesting to ask if non-planar corrections that account for the backreaction also spoil integrability. We nd a limit in which our Cuntz chain continues to admit extra conserved charges suggesting that integrability might survive.
68

Pure Yang-Mills amplitudes in 5 Dimensions : A study of vector boson amplitudes at 4 and 5 points

Voutouras, Athanasios January 2023 (has links)
In this text we explore the case of pure Yang-Mills amplitudes in 5 spacetime dimensions for vector particles. Extending current toolsets such as the Spinor-Helicity formalism in 5D would be beneficial to the study of the various cases of super Yang-Mills and supergravity. In this text we provide an expression for the 5D BCFW shifts and test them in the 4-point setting. A method for obtaining the 5-point gluon amplitude is presented as well as a way to classify possible building blocks of the ansatz. We also provide a non-trivial expression for the 5-point case. The text begins with a short review of Spinor-Helicity formalism in 4D is given at the beginning followed by a discussion of its extension to 5D. Next, we review the pure Yang-Mills theory and modern methods of amplitude calculations. Finally we discuss our methods and results. / Vi utforskar fallet med rena Yang-Mills-amplituder i 5 rymdtidsdimensioner för vektorpartiklar. Utvidgningen av Spinor-Helicity-formalismen i 5D skulle vara fördelaktig för studiet av de olika fallen av super Yang-Mills och supergravitation. I denna avhandling ger vi ett uttryck för 5D BCFW-skiften och tillämpar dem i 4-punktsinställningen. Vi presenterar en metod för att erhålla 5-punkts gluonamplituden och ett sätt att klassificera möjliga byggstenar i ansatsen. Med hjälp av dessa utvecklar vi ett icke-trivialt uttryck för 5-punktsfallet i 5D SH-variabler. Texten börjar med en kortöversikt över Spinor-Helicity-formalismen i 4D som ges i början följt av en diskussion om dess utvidgning till 5D. Därefter granskar vi den rena Yang-Mills-teorin och moderna metoder för amplitudberäkningar och slutligen diskuterar vi våra metoder och resultat
69

Super Yang-Mills theories on the lattice

Bibireata, Daniel 13 July 2005 (has links)
No description available.
70

Aspectos não perturbativos das teorias de Yang-Mills. / Non-perturbative aspects of Yang-Mills theory

Rodrigo Ferreira Sobreiro 27 February 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Alguns aspectos não perturbativos das teorias de Yang-Mills puras em quatro dimensões Euclideanas, quantizadas no calibre de Landau, são estudados analiticamente. Por pura entendemos a teoria na ausência de matéria (férmions). Em particular, ivestigamos a geração dinâmica de massa para os gluons devido a presença de condensados de dimensão dois. Este estudo é feito utilizando a técnica de operadores locais compostos no caso da ação de Yang-Mills, bem como, no caso da ação de Gribov-Zwanziger. Além deste estudo, uma investigação sobre as ambigüidades de Gribov nos calibres lineares covariantes é apresentada. No caso da ação de Yang-Mills, fizemos uma análise detalhada da técnica de opera-dores locais compostos quando introduzidos, simultaneamente, os operadores A&#956;aA&#956;a e fabcc*bcc. Através da teoria da renormalização algébrica, provamos a renormalizabilidade do modelo a todas as ordens em teoria de perturbações. Com o auxílio das equações do grupo de renormalização uma ação quântica efetiva é construída para os condensados <A&#956;aA&#956;a> e <fabcc*bcc>. Esta construção é feita utilizando a regularização dimensional em conjunto com o esquema de renormalização MS. Mostramos que um valor não trivial para estes condensados é favorecido dinamicamente, independentemente da escala escolhida. Cálculos explícitos, a um laço, são apresentados fornecendo estimativas numéricas para estes condensados e para a energia do vácuo. Através de um estudo via identidades de Ward, somos capazes de mostrar formalmente que a presença do condensado Overhauser, <fabcc*bcc>, é responsável pela quebra de transversalidade da polarização do vácuo. Contudo, o propagador do glúon permanece transverso, a todas as ordens em teorias de perturbações. Finalmente, esta análise é terminada com o cálculo explícito da correção, a um laço, à massa do glúon, devido a presença destes condensados. O resultado é que existe uma quebra na degenerescência da massa entre gluons Abelianos e não Abelianos. Esta quebra, devido a massa não Abeliana ser maior que a Abeliana, pode ser interpretada como uma evidência da dominância Abeliana no calibre de Landau. Com relação à ação de Gribov-Zwanziger sem a inclusão de condensados, começamos por efetuar cálculos explícitos. Mostramos formalmente que, a um laço, a energia do vácuo será sempre positiva, independentemente do esquema de renormalização escolhido e da escala. Apresentamos uma discussão sobre a procura de soluções da condição de horizonte no esquema MS, a um e dois laços, e as respectivas dificuldades encontradas. Em seguida, mostramos, através da teoria de renormalização algébrica, que a inclusão do operador A&#956;aA&#956;a na ação de Gribov-Zwanziger via o formalismo LCO é renormalizável a todas as ordens em teoria de perturbações. Tentativas de resolver as equações de gap são apresentadas no esquema de renormalização MS a um laço. Mostramos formalmente que, para a condição de horizonte, não existem soluções para <A&#956;aA&#956;a> < 0 e somente uma solução para <A&#956;aA&#956;a> > 0 pode existir. Contudo, no esquema MS, não fomos capazes de encontrar esta solução explicitamente. Desta forma, uma aprimoração do esquema de renormalização é feita de forma a minimizar a dependência no esquema escolhido. Nesta otimização encontramos a solução no limite MS bem como para o caso em que a dependência no esquema de renormalização é mínima. Em ambos os casos, a energia do vácuo se mostra positiva e o condensado <A&#956;aA&#956;a> > 0. Após os cálculos explícitos, uma discussão sobre as conseqüências físicas de um parâmetro de Gribov não nulo é apresentada. Finalmente, apresentamos um estudo das ambiguidades de Gribov nos calibres lineares covariantes para o caso em que &#945;<<1, onde &#945; é o parâmetro de calibre. Após identificar uma região no espaço funcional das configurações na qual não existem cópias de Gribov próximas, efetuamos a respectiva restrição da integral de caminho. Como efeito no nível árvore, o propagador do glúon transverso se torna suprimido no limite infravermelho devido a presença do horizonte de Gribov. A componente longitudinal se mostra suprimida devido a geração dinâmica de massa, associada ao condensado <A&#956;aA&#956;a>. Ainda, diferentemente do calibre de Landau, o propagador dos campos fantasmas não apresenta conexão com forças de longo alcance. Em contrapartida, uma função de Green singular no infravermelho, relacionada ao horizonte, é identificada e pode ser associada a forças de longo alcance. Por fim, todos os resultados do calibre de Landau são recuperados no limite &#945;&#8594;0.. / Some nonperturbative aspects of Euclidean Yang-Mills theories in four dimensions,quantized in the Landau gauge, are analytically studied. In particular, we investigate the dynamical mass generation for the gluons due to the presence of dimension two condensates. This study is performed in the framework of the local composite operator technique in the case of the Yang-Mills action as well as in the case of the Gribov-Zwanziger action. Further, an investigation of the Gribov ambiguities in the linear covariant gauges is presented. In the case of the Yang-Mills action, we perform a detailed analysis of the local composite operator formalism when the operators AaAa and fabccbcc are simultaneously introduced. Using the algebraic renormalization theory, we prove the renormalizability of the model trough all orders in perturbation theory. With the help of the renormalization group equations, a quantum efective action for the condensates <AaAa> and <fabccbcc> is constructed. This construction is performed by means of the dimensional regularization in the MS renormalization scheme. We show that non vanishing condensates values are dynamically favored, independently of the chosen scale. Explicit one loop computations are then presented, providing estimates for the condensates as well as for the vacuum energy. With the help of suitable Ward identities, we are able to normally show that the presence of the condensate <fabccbcc> is responsible for the breaking of the transversality of the vacuum polarization. However, the gluon propagator remains transverse, trough all orders in perturbation theory. Finally, we end this analysis with the explicit computation of the one loop correction to the efective gluon mass. The result is that, due to the condensate <fabccbcc>, the Abelian and the non Abelian sectors acquire diferent masses. Since the non Abelian mass is larger than the Abelian one, this feature can be interpreted as an evidence for the Abelian dominance principle in the Landau gauge. With respect to the Gribov-Zwanziger action, we start our analysis without taking into account the condensate. We show that, at one loop order, the vacuum energy is always positive, independently of the renormalization scheme and scale. We also present attempts to solve the one and two loops horizon condition in the MS scheme, and also the respective obstacles of it. Later, using the algebraic renormalization theory, we show, to all orders in perturbation theory, the renormalizability of the Gribov-Zwanziger action when the composite operator AaAa is included in the framework of the local composite operator technique. Attempts to solve the one loop gap equations in the MS scheme are then presented. We show that there are no solutions for <AaAa> < 0 while for <AaAai> 0 there is only one possible solution for the horizon condition. However, in the MS scheme, we were not able to find explicitly that solution. As an improvement, an optimization of the renormalization scheme is performed in the sense of minimizing the renormalization scheme dependence. In that approach the MS limit solution was found as well as the solution with minimal dependence on the renormalization scheme. In both cases, the vacuum energy shows itself to be positive while the condensate <AaAa> > 0. A discussion of the consequences of a nonvanishing Gribov parameter is then provided. Finally, we present a study of the Gribov ambiguities in the linear covariant gauges for the case &#945;<<1, where &#945; is the gauge parameter. After the identification of a region in field space where there are no close Gribov copies, we perform the respective restriction in the path integral. As a tree level efect, the transverse gluon propagator turns out to be infrared suppressed, due to the presence of the Gribov horizon. The longitudinal component shows itself to be infrared suppressed due to the dynamical mass, associated with the condensate <AaAa>. Further, diferently of the Landau gauge, the ghost propagator is not related to the appearance of long range forces. Instead, an infrared singular Green function related to the Gribov horizon is identifed. This Green function can be associated with long range forces. At the end, all Landau gauge results can be recovered taking the limit &#945;&#8594;0.

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