In this work aspects of the classical Connes-Lott non-commutative standard model are examined. In particular the relationship between the chiral structure of the standard model and the condition of Poincaré Duality is investigated. Then the natural prediction of an additional force in the non-commutative standard model is explained and the consequences calculated. Finally the attempts at grand unification within the non-commutative framework are reviewed and extended.

The goal of this thesis is to give an introduction to the geometric picture of bivariant K-theory developed by Emerson and Meyer building on the ideas Connes and Skandalis, and then to apply this machinery to give a geometric proof of a result of Emerson. We begin by giving an overview of topological K-theory, necessary for developing bivariant K-theory. Then we discuss Kasparov's analytic bivariant K-theory, and from there develop topological bivariant K-theory. In the final chapter we state and prove the result of Emerson. / Graduate

No description available.

La théorie des pavages apériodiques a connu des développements rapides depuis les années 1980, avec la découvertes d'alliages métalliques cristallisant dans une structure quasi-périodique.Dans cette thèse, on étudie particulièrement deux méthodes de construction de pavages : par coupe et projection, et par substitution. Deux angles d'approche sont développés : l'étude de la fonction de complexité, et l'étude métrique de l'espace de pavages.Dans une première partie, on calcule l'asymptotique de la fonction de complexité pour des pavages coupe et projection, généralisant ainsi des résultats connus en dynamiques symbolique pour la dimension 1. On montre que pour un pavage coupe et projection canonique N sur d sans période, la complexité croît (à des constantes près) comme n à la puissance a, où a est un entier compris entre d et N-d.Ensuite, on se base sur une construction de Pearson et Bellissard qui construisent un triplet spectral sur les ensembles de Cantor ultramétriques. On suit leur construction dans le cas d'ensembles de Cantor auto-similaires. Elle s'applique en particulier aux transversales d'espaces de pavages de substitution.Enfin, on fait le lien entre la distance usuelle sur l'enveloppe d'un pavage et la complexité de ce pavage. Les liens entre complexité et métrique permettent de donner une preuve directe du fait suivant : la complexité des pavages de substitution apériodiques de dimension d croît comme n à la puissance d.La question de liens entre la complexité et la topologie (et pas seulement avec la distance) reste ouverte. Nous apportons cependant des réponses partielles dans cette direction. / Since the 1980s, the theory of aperiodic tilings developed quickly, motivated by the discovery of metallic alloys which crystallize in an aperiodic structure. This highlighted the need for new models of crystals.Two models of aperiodic tilings are specifically studied in this dissertation. First, the cut-and-project method, then the inflation and substitution method. Two point of view are developed for the study of these objects: the study of the complexity function associated to a tiling, and the metric study of the associated tiling space.In a first part, the asymptotic behaviour of the complexity function for cut-and-project tilings is studied. The results stated here generalize formerly known results in the specific case of dimension 1. It is proved that for an (N,d) canonical projection tiling without periods, the complexity grows like n to the a, with a an integer greater or equal to d but lesser or equal to N-d.A second part is based on a construction by Pearson and Bellissard of a spectral triple for ultrametric Cantor sets. Their construction is applied to self-similar Cantor sets. It applies in particular to the transversal of substitution tiling spaces.In a last part, the links between the complexity function of a tiling and the usual distance on its associated tiling space are made explicit. These links can provide a direct and complete proof of the following fact: the complexity of an aperiodic d-dimensional substitution tiling grows asymptotically as n to the d, up to constants. These links between complexity and distance raises the question of links between complexity and topology. Partial answers are given in this direction.

No description available.

Submitted by Vasti Diniz (vastijpa@hotmail.com) on 2017-09-11T13:46:47Z No. of bitstreams: 1 arquivototal.pdf: 4626287 bytes, checksum: 422f70b41a38fd74eb6520e392f6d65b (MD5) / Made available in DSpace on 2017-09-11T13:46:47Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4626287 bytes, checksum: 422f70b41a38fd74eb6520e392f6d65b (MD5) Previous issue date: 2017-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work, we developed a complete study on the relativistic Landau model and non-commutative geometry, the latter was derived from level projection, in order to describe curved graphene systems. In developing of the theory, we address the problem of the eigenvalues from the relativistic Dirac-Landau operador on the sphere with a magnetic monopole in its center. The relativistic fuzzy spheres are introduced using the eigenstates of the relativistic Landau levels and we compare it with non-relativistic cases. Under mass deformation, the fuzzy spheres relative to the relativistic symmetric Landau levels change their sizes, however zero-modes there are no variation of size for the corresponding fuzzy sphere. Consecutively we verify that the relativistic Landau model and non-relativistic system of Pauli-Schr odinger are related by gauge transformation SU(2). And nally, the application of the whole theoretical graphene's framework show a simmetric spectrum with respect to its zero energy, and it maintains itself under mass deformation. On the other hand, the in uence of the mass parameters M 6= 0 on the four fuzzy spheres (two for each valley) is such that, if n 6= 0, two of them are enlarged and the other two are diminished, but for n = 0 the fuzzy spheres (at M) do not change their sizes. / Neste trabalho, desenvolvemos um estudo completo do modelo de Landau relativ stico e da geometria n~ao-comutativa, esta ultima derivada a partir da proje c~ao de n vel, a m de descrever sistemas curvos de grafeno. No desenvolvimento da teoria, abordamos o problema de autovalores do operador Dirac-Landau relativ stico sobre uma esfera com um monopolo magn etico em seu centro. As esferas fuzzy relativ sticas s~ao introduzidas usando-se os autoestados dos n veis de Landau relativ sticos e uma compara c~ao e feita com os casos n~ao-relativ sticos. Sob deforma c~ao da massa, as esferas fuzzy correspondentes a n veis de Landau relativ sticos sim etricos modi cam seus tamanhos, mas para modos-zero n~ao h a varia c~ao do tamanho para a esfera fuzzy correspondente. Em sequ^encia veri ca-se que o modelo de Landau relativ stico e o sistema n~ao-relativ stico de Pauli-Schr odinger est~ao relacionados por uma transforma c~ao de gauge SU(2). Finalmente, a aplica c~ao de todo o esse arcabou co te orico no grafeno, mostra que seu espectro e sim etrico com respeito a energia zero, e mant em-se mesmo sob deforma c~ao da massa. Por outro lado, a in u^encia do par^ametro de massa M 6= 0 nas quatro esferas fuzzy (2 para cada vale) e tal que, se n 6= 0, duas delas aumentam e as outras duas diminuem, mas para n = 0 as esferas fuzzy (em M) n~ao mudam seus tamanhos

The thrust of this thesis is to describe base change BC_E/F at the level of chamber homology and K-theory for some p-adic groups, such as SL(2,F), GL(1,F) and GL(2,F). Here F is a non-archimedean local field and E is a Galois extension of F. We have had to master the representation theory of SL(2) and GL(2) including the Langlands parameters. The main result is an explicit computation of the effect of base change on the chamber homology groups, each of which is constructed from cycles. This will have an important connection with the Baum-Connes correspondence for such p-adic groups. This thesis involved the arithmetic of fields such as E and F, geometry of trees, the homology groups and the Weil group W_F.

Quantenfeldtheorien, die auf Räumen mit nichtkommutierenden Koordinaten definiert sind, finden in den letzten Jahren zunehmend Interesse. Mögliche Anwendungen dieser Modelle gibt es unter anderem in der Stringtheorie, der Phänomenologie der Elementarteilchen und in der Festkörperphysik. In der vorliegenden Arbeit untersuchen wir nichtstörungstheoretisch solche nichtkommutativen Feldtheorien mit Hilfe von Monte-Carlo Simulationen. Wir betrachten eine zweidimensionale reine U(1) Eichfeldtheorie und eine dreidimensionale skalare Feldtheorie. Dazu bilden wir die entsprechenden Gittertheorien auf dimensional reduzierte Modelle ab, die mittels N x N Matrizen formuliert sind. Die 2d Eichtheorie auf dem Gitter ist äquivalent zum twisted Eguchi-Kawai Modell, das wir für N=25 bis 515 simulierten. Wir beobachteten ein deutliches Skalierungsverhalten der Ein- und Zweipunktfunktionen von Wilson-Schleifen sowie von Zweipunktfunktionen von Polyakov-Linien bei großen N. Die Zweipunktfunktionen stimmen mit einer universellen Wellenfunktionsrenormierung überein. Der Doppel-Skalierungslimes bei N gegen unendlich entspricht dem Kontinuumslimes in der nichtkommutativen Gittereichtheorie. Das beobachtete Skalierungsverhalten bei großen N zeigt die nichtstörungstheoretische Renormierbarkeit dieser nichtkommutativen Feldtheorie. Für kleine Flächen gilt das Flächengesetz der Wilson-Schleifen wie in der kommutativen 2d planaren Eichtheorie. Für große Flächen finden wir jedoch stattdessen ein oszillierendes Verhalten. In diesem Bereich wächst die Phase der Wilson-Schleifen linear mit der Fläche. Identifiziert man den Nichtkommutativitätsparameter mit einem inversen Magnetfeld, entspricht dies dem Aharonov-Bohm-Effekt. Als nächstes untersuchen wir das 3d lambda phi^4 Modell mit zwei nichtkommutierenden Dimensionen. Wir analysieren das Phasendiagramm. Unsere Ergebnisse stimmen mit einer Vermutung von Gubser und Sondhi in vier Dimensionen überein. Sie sagen vorher, daß sich der geordnete Bereich in eine uniforme und eine nichtuniforme Phase aufspaltet. Desweiteren zeigen wir Ergebnisse für Korrelatoren und der Dispersionsrelation. In der nichtkommutativen Feldtheorie ist die Lorentz-Symmetrie explizit gebrochen, was zu einer deformierten Dispersionsrelation führt. In der Ein-Schleifen Störungstheorie ergibt sich ein zusätzlicher infrarot divergenter Term. Unsere Daten bestätigen dieses störungstheoretische Ergebnis. Wir bestätigen ebenso eine Beobachtung von Ambjorn und Catterall, daß eine nichtuniforme Phase auch in zwei Dimensionen existiert, obwohl dies eine spontane Brechung der Translationssymmetrie impliziert. / In the recent years there is a surge of interest in quantum field theories on spaces with non-commutative coordinates. The potential applications of such models include string theory, particle phenomenology as well as solid state physics. We perform a non-perturbative study of such non-commutative field theories by the means of Monte Carlo simulations. In particular we consider a two dimensional pure U(1) gauge field theory and a three dimensional scalar field theory. To this end we map the corresponding lattice theories on dimensionally reduced models, which are formulated in terms of N x N matrices. The 2d gauge theory on the lattice is equivalent to the twisted Eguchi-Kawai model, which we simulated at N ranging from 25 to 515. We observe a clear large N scaling for the 1- and 2-point function of Wilson loops, as well as the 2-point function of Polyakov lines. The 2-point functions agree with a universal wave function renormalization. The large N double scaling limit corresponds to the continuum limit of non-commutative gauge theory, so the observed large N scaling demonstrates the non-perturbative renormalizability of this non-commutative field theory. The area law for the Wilson loops holds at small physical area as in commutative 2d planar gauge theory, but at large areas we find an oscillating behavior instead. In that regime the phase of the Wilson loop grows linearly with the area. This agrees with the Aharonov-Bohm effect in the presence of a constant magnetic field, identified with the inverse non-commutativity parameter. Next we investigate the 3d lambda phi^4 model with two non-commutative coordinates and explore its phase diagram. Our results agree with a conjecture by Gubser and Sondhi in d=4, who predicted that the ordered regime splits into a uniform phase and a phase dominated by stripe patterns. We further present results for the correlators and the dispersion relation. In non-commutative field theory the Lorentz invariance is explicitly broken, which leads to a deformation of the dispersion relation. In one loop perturbation theory this deformation involves an additional infrared divergent term. Our data agree with this perturbative result. We also confirm the recent observation by Ambjorn and Catterall that stripes occur even in d=2, although they imply the spontaneous breaking of the translation symmetry.

Es werden verschiedene Aspekte interner magnetischer Hintergrundfelder in Theorien offener Strings diskutiert. Phaenomenologisch und konzeptionell interessante Eigenschaften solcher Vakua, die Brechung von Supersymmetrie, Eichsymmetrie und chiraler Symmetrie, werden auf ganz generische Weise behandelt. Dann wird eine Spezialisierung auf Typ I Modelle, kompaktifiziert auf Tori und Bahnfaltigkeiten, durchgefuehrt. Daraus wird eine Methode gewonnen zur Konstruktion von Typ I Vakua mit attraktiven effektiven Feldtheorien als Niederenergienaeherungen, sowohl supersymmetrische wie nicht supersymmetrische Modelle mit chiralen Fermionspektren und Eichgruppen aehnlich dem Standardmodell oder einer vereinheitlichenden Verallgemeinerung desselben. Die am weitesten entwickelten Beispiele kombinieren magnetische Felder mit NSNS B-Feldern auf Bahnfaltigkeiten. Zuletzt wird noch eine verwandte Klasse von Modellen besprochen, die zwar eher weniger vielversprechende phaenomenologische Perspektiven bietet, aber einige konzeptionelle Spezialitaeten aufweist. In diesen Kompaktifizierungen werden asymmetrische Rotationen geeicht, so dass D-branen mit unterschiedlichen Werten fuer die magnetischen Felder auf ihrem Weltvolumen identifiziert werden, womit die Unterscheidung von kommutativen und nicht kommutativen Geometrien verlorengeht. / We discuss various aspects of internal magnetic background fields in open string theories. Phenomenologically and conceptually interesting properties of such string theory backgrounds, supersymmetry and gauge symmetry breaking, chiral fermion spectra and noncommutativity of the internal compactification manifolds, are treated in a rather generic framework. We then specialize to type I compactifications on tori and toroidal orbifolds with magnetic fields on the internal space. This allows to develop a strategy for constructing type I vacua with attractive low energy field theories which may either be supersymmetric or not and contain chiral spectra and gauge groups close to the Standard Model or some grand unified generalization thereof. The most sophisticated version uses magnetic fields and NSNS B-fields on orbifold spaces giving rise to a plethora of promising examples for semi-realistic string compactifications. We finally also present a related class of asymmetric orbifolds of type I which are of little phenomenological interest but still display certain interesting features. The asymmetric rotations which are gauged in these models identify D-branes with different values for the magnetic field on their world volume, such that the distinction of commutative and noncommutative internal geometries is lost.

Dans cette thèse, nous nous intéressons à la géométrie non-commutative - aux triplets spectraux en particulier - comme moyen d'unifier gravitation et modèle standard de la physique des particules. Des triplets spectraux permettant une telle unification on déjà été construits dans le cas des variétés riemanniennes. Il s'agit donc ici de généraliser au cas des variétés semi-riemanniennes, et d'appliquer ensuite au cas lorentzien, qui est d'une importance particulière en physique. C'est ce que nous faisons dans la première partie de la thèse, ou le passage du cas riemannien au cas semi-riemannien nous oblige à nous intéresser à des espaces vectoriels de signatures indéfinies (et non définies positives), dits espaces de Krein. Ceci est une conséquence de notre étude des algèbres de Clifford indéfinies et des structures Spin sur variétés semi-riemanniennes. Nous généralisons ensuite les triplets spectraux en triplets dits indéfinis en conséquence de cela. Dans la deuxième partie de la thèse, nous appliquons le formalisme des formes différentielles non-commutatives à nos triplets indéfinis pour formuler des théories de jauge non-commutatives sur espace-temps lorentzien. Nous montrons ensuite comment obtenir le modèle standard. / The subject of this thesis is noncommutative geometry - more specifically spectral triples - and how it can be used to unify General Relativity with the Standard Model of particle physics. This unification has already been achieved with spectral triples for Riemannian manifolds. The main concern of this thesis is to generalize this construction to semi-Riemannian manifolds generally, and Lorentzian manifolds in particular. The first half of this thesis will thus be dedicated to the transition from Riemannian to semi-Riemannian manifolds. This entails a study of Clifford algebras for indefinite vector spaces and Spin structures on semi-Riemannian manifolds. An important consequence of this is the introduction of complex vector spaces of indefinite signature. These are the so-called Krein spaces, which will enable us to generalize spectral triples to indefinite spectral triples. In the second half of this thesis, we will apply the formalism of noncommutative differential forms to indefinite spectral triples to construct noncommutative gauge theories on Lorentzian spacetimes. We will then demonstrate how to recover the Standard Model.