Submitted by LUIS ALBERTO YPANAQUE ROCHA null (luis.12yr@gmail.com) on 2016-05-25T17:27:19Z No. of bitstreams: 1 Dissertação. Ypanaque.pdf: 426914 bytes, checksum: 330fd0a0d64619b7c70a34888c1162ee (MD5) / Rejected by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: O arquivo submetido está sem a ficha catalográfica e sem a folha de aprovação. A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação. Corrija esta informação e realize uma nova submissão contendo o arquivo correto. Agradecemos a compreensão. on 2016-05-31T13:31:32Z (GMT) / Submitted by LUIS ALBERTO YPANAQUE ROCHA null (luis.12yr@gmail.com) on 2016-06-06T17:34:37Z No. of bitstreams: 2 Dissertação. Ypanaque.pdf: 426914 bytes, checksum: 330fd0a0d64619b7c70a34888c1162ee (MD5) Ata da defessa.pdf: 500723 bytes, checksum: 7683fb4add13703ee3ec0f777ed0b2c9 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-06-08T16:39:04Z (GMT) No. of bitstreams: 1 rocha_lay_me_ift.pdf: 941453 bytes, checksum: b84df75619a0fb66d074735532b365af (MD5) / Made available in DSpace on 2016-06-08T16:39:04Z (GMT). No. of bitstreams: 1 rocha_lay_me_ift.pdf: 941453 bytes, checksum: b84df75619a0fb66d074735532b365af (MD5) Previous issue date: 2016-04-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho nós estudamos ações para a superpartícula e a supercorda usando vínculos twistóricos. Escrevemos as cargas BRST para a superpartícula e a supercorda em dez dimensões, e a carga BRST para um modelo de partícula em quatro dimensões com a finalidade de fazer algumas comparações. Começamos mostrando como os twistors aparecem como objetos geométricos que parametrizam SO(4)/U(2), e usamos uma generalização deste fato para dez dimensões e assim construir as teorías correspondentes. Então mostramos como obter as ações de espinores puros para a superpartícula e a supercorda em dez dimensões por meio de gauge-twisting e gauge-fixing da teoría inicial. / In this work we study actions for the superparticle and the superstring using twistor-like constraints. We write BRST charges for the superparticle and the superstring in ten dimensions, and the BRST charge for a particle model in four dimensions in order to make some comparisons. We start showing how twistors appear as geometrical objects parametrizing SO(4)/U(2), and use a generalization of this fact to ten dimensions to construct the corresponding theories. We then show how to obtain the pure spinor superparticle and superstring actions in ten dimensions by gauge-twisting and gauge-fixing the initial theory.

Submitted by MATHEUS LOSS LIZE (matheuslize@icloud.com) on 2018-06-25T14:57:23Z No. of bitstreams: 1 Thesis Final.pdf: 1131929 bytes, checksum: a010126b1d56e2526a965d0e67aed302 (MD5) / Rejected by Hellen Sayuri Sato null (hellen@ift.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo: - título e titulo alternativo estão em inglês. Título alternativo, neste caso, deve ser em português. Por favor, utilize maiúscula apenas na palavra inicial do titulo e em caso de siglas ou nomes próprio - Seu nome foi preenchido Loss Lize, Matheus. Loss é o sobrenome do seu pai? A entrada deve ser pelo sobrenome do pai. Acho que no seu caso, o correto seria Lize, Matheus Loss on 2018-06-29T17:55:18Z (GMT) / Submitted by MATHEUS LOSS LIZE (matheuslize@icloud.com) on 2018-06-29T18:23:23Z No. of bitstreams: 1 Thesis Final.pdf: 1131929 bytes, checksum: a010126b1d56e2526a965d0e67aed302 (MD5) / Approved for entry into archive by Hellen Sayuri Sato null (hellen@ift.unesp.br) on 2018-06-29T18:45:49Z (GMT) No. of bitstreams: 1 lize_ml_dr_ift.pdf: 1131929 bytes, checksum: a010126b1d56e2526a965d0e67aed302 (MD5) / Made available in DSpace on 2018-06-29T18:45:49Z (GMT). No. of bitstreams: 1 lize_ml_dr_ift.pdf: 1131929 bytes, checksum: a010126b1d56e2526a965d0e67aed302 (MD5) Previous issue date: 2017-02-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Neste trabalho revisamos as amplitudes de MHV no contexto da teoria de super-Yang-Mills. Nós estudamos as simetrias das amplitudes de MHV no espaço de twistors como uma motivação para introduzir a teoria de cordas com twistors . A teoria de cordas com twistors feita por Nathan Berkovits [3] é revisada e uma fórmula geral é dada para calcular amplitudes de espalhamento com n gluons. No final, a partir desta fórmula deduzimos a amplitude de MHV. / In this work we review the maximal helicity violating (MHV) scattering amplitude in the context of super-Yang-Mills theory. We study the symmetries of the MHV amplitude in the twistor space as a motivation to introduce the twistor string theory. The twistor string action introduced by Nathan Berkovits [3] is reviewed and also a general formula is given for the scattering amplitude with n gluons. In the end, the MHV amplitude is derived from this formula. / CNPq: 132620/2015-4.

Le théorème de Gauss sur les sommes de 3 carrés relie le nombre de points entiers primitifs sur la sphère de rayon la racine carrée de n au nombre de classes d'un ordre quadratique imaginaire. En 2011, Edixhoven a esquissée une preuve du théorème de Gauss en utilisant une approche de la géométrie arithmétique. Il a utilisé l'action du groupe orthogonal spécial sur la sphère et a donné une bijection entre l'ensemble des SO3(Z)-orbites de tels points, si non vide, avec l'ensemble des classes d'isomorphisme de torseurs sous le stabilisateur. Ce dernier ensemble est un groupe, isomorphe au groupe des classes d'isomorphisme de modules projectifs de rang 1 sur l'anneau Z[1/2, √- n], ce qui donne une structure d'espace affine sur l'ensemble des SO3(Z)-orbites sur la sphère. Au chapitre 3 de cette thèse, nous donnons une démonstration complète du théorème de Gauss suivant les travaux d'Edixhoven. Nous donnons aussi une nouvelle preuve du théorème de Legendre sur l'existence d'une solution entière primitive de l'équation x2 + y2 + z2 = n en utilisant la théorie des faisceaux. Nous montrons au chapitre 4 comment obtenir explicitement l'action, donnée par la méthode des faisceaux, du groupe des classes sur l'ensemble des SO3(Z)-orbites sur la sphère en termes de SO3(Q). / Gauss's theorem on sums of 3 squares relates the number of primitive integer points on the sphere of radius the square root of n with the class number of some quadratic imaginary order. In 2011, Edixhoven sketched a different proof of Gauss's theorem by using an approach from arithmetic geometry. He used the action of the special orthogonal group on the sphere and gave a bijection between the set of SO3(Z)-orbits of such points, if non-empty, with the set of isomorphism classes of torsors under the stabilizer group. This last set is a group, isomorphic to the group of isomorphism classes of projective rank one modules over the ring Z[1/2, √- n]. This gives an affine space structure on the set of SO3(Z)-orbits on the sphere. In Chapter 3 we give a complete proof of Gauss's theorem following Edixhoven's work and a new proof of Legendre's theorem on the existence of a primitive integer solution of the equation x2 + y2 + z2 = n by sheaf theory. In Chapter 4 we make the action given by the sheaf method of the Picard group on the set of SO3(Z)-orbits on the sphere explicit, in terms of SO3(Q). / De stelling van Gauss over sommen van 3 kwadraten relateert het aantal primitieve gehele punten op de bol van straal de vierkantswortel van n aan het klassengetal van een bepaalde imaginaire kwadratisch orde. In 2011 schetste Edixhoven een ander bewijs van deze stelling van Gauss metbehulp van aritmetische meetkunde. Hij gebruikte de actie van de special orthogonale groep op de bol en gaf een bijectie tussen de verzameling van SO3(Z)-banen van dergelijke punten, als die niet leeg is, met de verzameling van isomor_e klassen van torsors onder de stabilisator groep. Deze laatste verzameling is een groep, isomorf met de groep van isomor_e klassen van projectieve rang _e_en modulen over de ring Z[1/2, √- n]. Dit geeft een a_ene ruimte structuur op de verzameling van SO3(Z)-banen op de bol. In Hoofdstuk 3 geven we een volledig bewijs van de stelling van Gauss zoals geschetst door Edixhoven, en een nieuw bewijs van Legendre's stelling over het bestaan van een primitieve gehele oplossing van de vergelijking x2 +y2 +z2 = n met schoven theorie. In hoofdstuk 4 maken we de werking gegeven door de schoven theorie van de Picard groep op de verzameling van SO3(Z)-banen op de bol expliciet, in termen van SO3(Q).

In this review, several tools used in the study of super-Yang-Mills scattering amplitudes are discussed, namely spinor-helicity and (super)twistor variables. These variables are then implemented in string theories in 4D, and a suitable generalization to 10D using pure spinors is discussed. Dimensional reduction of this model to 4D is then performed, and some comparisons to other 4D models are drawn.

This thesis carries out a detailed investigation of the action for pure Yang-Mills theory which L. Mason formulated in twistor space. The rich structure of twistor space results in greater gauge freedom compared to the theory in ordinary space-time. One particular gauge choice, the CSW gauge, allows simplifications to be made at both the classical and quantum level. The equations of motion have an interesting form in the CSW gauge, which suggests a possible solution procedure. This is explored in three special cases. Explicit solutions are found in each case and connections with earlier work are examined. The equations are then reformulated in Minkowski space, in order to deal with an initial-value, rather than boundary-value, problem. An interesting form of the Yang-Mills equation is obtained, for which we propose an iteration procedure. The quantum theory is also simplified by adopting the CSW gauge. The Feynman rules are derived and are shown to reproduce the MHV diagram formalism straightforwardly, once LSZ reduction is taken into account. The three-point amplitude missing in the MHV formalism can be recovered in our theory. Finally, relations to Mansfield’s canonical transformation approach are elucidated.

Un des aspects fascinants de la théorie des cordes, c'est qu'elle vit dans l'espace-temps de dix dimensions. Mais cela implique que, pour la relier à des observations phénoménologiques, elle devrait ȇtre compactifiées à quatre dimensions. Un cas particulièrement riche, mais toujours faisable correspond à la compactification sur une variété de Calabi-Yau qui donne à basse énergie une théorie effective avec la supersymétrie N=2. L'action de cette théorie est complètement déterminée par la métrique sur son espace des modules qui comporte deux composantes correspondant aux multiplets vectoriels et hypermultiplets. La première est classiquement exacte et bien comprise, alors que la dernière reçoit des corrections quantiques et est connue de porter une géométrie compliquée quaternion-Kählerrienne. Dans cette thèse, nous présentons nos résultats sur la description complète non-perturbative de l'espace des modules des hypermultiplets. Nous montrons comment toutes les corrections quantiques, qui comprennent des contributions perturbatives d'une boucle ainsi que celles non-perturbatives venant des D-branes et NS5-branes, sont incorporées dans le cadre de l'approche twisteurielle. Ce cadre, que nous élaborons ici en détail, fournit une description mathématique puissante des variétés hyperkähleriennes et quaternion-Kähleriennes et il est indispensable pour la formulation de la géométrie non-perturbative de l'espace des modules des hypermultiplets. Nous présentons également de nouveaux résultats sur la dualité-S, symétrie miroir quantique, les connexions à des modèles intégrables et aux cordes topologiques.

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