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Dark Matter: The evidence for the existence of Dark Matter is compelling based on observations in Astrophysics and Cosmology, while the nature of Dark Matter in Particle Physics is still unclear. Direct Detection is a promising method to detect the recoil energy of nucleons from the scattering of Dark Matter, and indirect searches for Dark Matter put constraints on Dark Matter annihilation and decay, and they give hints about the properties of Dark Matter. We proposed a Millicharged Atomic Dark Matter model, in which the dark constituents of the hidden sector are bound into dark atoms by an unbroken hidden U(1) gauge field. This model is consistent with cosmological and astrophysical constraints, it has the potential to explain the results from the CoGeNT experiment, and it relaxes some tensions from other direct search experiments.UV/IR Divergences in Inflation: Studying the quantum corrections to the two point correlation function of curvature perturbations is an essential step to understand perturbation theory in curved space time. IR divergences may lead to possibly observable consequences in cosmology. By finding the correct way to impose UV and IR cutoffs, we manage to reach a consistent result that all three regularization schemes commonly used -- brute-force cutoff, dimensional regulation, and Pauli-Villars regularization -- all give the same quantum correction to the correlation function. By considering the IR divergences from entropy fields, we explore the effective field theory of inflation in the presence of such fields. / Matière Noire:Les observations actuelles en astrophysique et en cosmologie semblent démontrer l'existence de matière noire dans notre univers. Néanmoins, du point de vue des intéractions fondamentales en physique des particules, les propriétés d'une telle matière ne sont pas encore complètement établies. Les méthodes de détection directe et indirecte apportent de nouvelles limites sur les modes de desintégration de la matière noire et améliorent notre compréhension de celle-ci. Cette thèse propose un modèle de matière noire atomique millichargée, dans lequel l'atome est consitué de particules sombres fondamentales liées par une force de jauge invisible aux particules du modèle standard. Ce modèle est ensuite comparé aux contraintes mentionnées, et en particulier aux résultats de l'expérience CoGeNT, permettant ainsi une meilleure intégration des differentes données experimentales. Divergences ultraviolette et infrarouge dans l'inflation cosmologique:L'étude des corrections quantiques dans la fonction de corrélation de deux perturbations de la courbure spatiale est un ingrédient essentiel a la compréhension de la théorie des perturbations dans un espace-temps courbe. Les divergences infrarouge peuvent causer des effets mesurables en cosmologie. En choisissant de manière appropriée les bornes d'intégration d'énergie, les corrections de la fonction de corrélation sont calculées dans les trois grands procédures de régularisation. La théorie effective de l'inflation cosmologique est ensuite présentée avec les effets des divergences infrarouges des champs d'entropie.

<p> Spin networks arise in many areas of physics and are a key component in both the canonical formulation (loop quantum gravity) and the path-integral formulation (spin-foam gravity) of quantum gravity. In loop quantum gravity the spin networks are used to construct a countable basis for the physical Hilbert space of gravity. The basis states may be interpreted as gauge-invariant wavefunctionals of the connection. Evaluating the wavefunctional on a specific classical connection involves embedding the spin network into a spacelike hypersurface and finding the holonomy around the network. This is equivalent to evaluating a ''<i>g</i>-inserted'' spin network (a spin network with a group action acting on all of the edges of the network). The spin-foam approach to quantum gravity is a path-integral formulation of loop quantum gravity in which the paths are world-histories of embedded spin networks. Depending on the spin-foam model under consideration the vertex amplitude (the contribution a spin-foam vertex makes to the transition amplitude) may be represented by a specific simple closed spin network. The most important examples use the 6<i>j</i>-symbol, the 15<i>j</i>-symbol, and the Riemannian 10<i>j</i>-symbol. The semiclassical treatment of spin networks is the main theme of this dissertation. </p><p> To show that classical solutions of general relativity emerge in the appropriate limits of loop quantum gravity or spin-foam gravity requires knowledge of the semiclassical limits of spin networks. This involves interpreting the spin networks as inner products and then treating the inner products semiclassically using the WKB method and the stationary phase approximation. For any given spin network there are many possible inner product models which correspond to how the spin network is ''split up'' into pieces. For example the 6<i> j</i>-symbol has been studied in both a model involving four angular momenta (Aquilanti et al 2012) and a model involving twelve angular momenta (Roberts 1999). Each of these models offers advantages and disadvantages when performing semiclassical analyses. Since the amplitude of the stationary phase approximation relies on determinants they are easiest to calculate in phase spaces with the fewest dimensions. The phase, on the other hand, is easiest to compute in cases where all angular momenta are treated on an equal footing, requiring a larger phase space. </p><p> Surprisingly, the different inner product models are <i>not</i> related by symplectic reduction (the removal of a symmetry from a Hamiltonian system). There <i>is</i> a connection between the models, however. On the level of linear algebra the connection is made by considering first not inner products but matrix elements of linear operators. A given matrix element can then be interpreted as an inner product in two different Hilbert spaces. We call the connection between these two inner product models the ''remodeling of an inner product.'' The semiclassical version of an inner product remodeling is a generalization of the idea that the phase space manifold that supports the semiclassical approximation of a unitary operator may be considered the graph of a symplectomorphism. We use the manifold that supports the semiclassical approximation of the linear map to ''transport'' features from one space to another. Using this transport procedure we can show that the amplitude and phase calculations in the phase spaces for the two models are identical. The asymptotics of a complicated spin network, and thus the fundamental amplitudes of loop quantum gravity and spin-foam gravity, may be computed by first setting up an inner product remodeling and then picking and choosing which features of the calculation to perform in which space. </p><p> In this dissertation we first introduce the remodeling of an inner product and the semiclassical features of the remodeling. We then apply the remodeling to the well-studied cases of the 3<i>j</i>-symbol and the 6<i> j</i>-symbol. Finally we explore how the remodel procedure applies to more complicated spin networks such as the 15<i>j</i>-symbol and the <i>g</i>-inserted spin networks of loop quantum gravity.</p>

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<p> This dissertation comprise of two chapters on the macroeconomic effect of natural resource rents. Specifically, we focus on the effect of resource rents on human capital accumulation. In chapter one, we present a new mechanism for the curse of natural resources, i.e., "why natural resource rents if distributed as transfers to individuals' income might retard economic growth and development: their effect on incentives to invest in human capital". Extending an OLG model for this purpose, we show that the windfall rents from natural resources, when transferred directly to citizens distort their incentives away from accumulating the optimum level of human capital and thus from economic growth. This increases the chance of a low-level equilibrium trap and reduces the chance of converging to a higher income per capita in the long run.</p><p> In chapter two, we present a dynamic panel data model, and a cross section model to see the effect of transfers in countries with high natural resource rents per person on human capital accumulation. We use tertiary education as a human capital indicator, since at this educational level, people choose to accumulate professional skills and direct their talents to sectors with the highest expected return. Using a dynamic panel data model for five years averages of tertiary education, one can see that the combined effect of government transfers and natural resource rents per labor have a negative and significant effect on human capital. However, using a cross section analysis for the same purpose, one can see that not only the combined effect of resource rents per labor and government transfers have a negative and significant effect on tertiary education, but also resource rents per labor alone have a negative and significant effect on tertiary education. Our cross section results coincide with the natural resource curse literature as it shows that resource rents have a long-term negative effect on social capital investments such as tertiary education. </p>

This thesis suggests that problematic dualistic frameworks are challenged in writing that, in engaging issues of embodiment, does not overlook the biological sciences. This thesis first introduces a brief history of dualistic frameworks, especially in the context of critical animal studies. Each chapter that follows engages a core theme of embodiment: Jacques Derrida's concept of autoimmunity; Sigmund Freud's work on depression, hysteria, and PTSD, along with Elizabeth Wilson's reading of Freud’s work as psychosomatics; and the work of David Wills, whose theory of dorsality suggests an original technicity, or automaticity, at work at the origin of the human species and at the origin of biological life itself. Significant in each chapter is the way in which each theorist draws on concepts, research, or analogies that come from biology in order to strengthen his or her concepts of embodiment.

Following the holographic QCD model of Sakai and Sugimoto, we analyze the mesonic spectrum of a large N thermal QCD model in the dual string theory. After a T-dual transformation, the background of the ten-dimensional spacetime contains N D4-branes and $N_f$ D6/D6-branes and the internal manifold consists of a resolved-deformed conifold whose $\psi$ direction is the analogue of the compact cycle of the Sakai-Sugimoto's geometry. Using the probe approximation, we study the DBI action of the D6-branes and, by restricting the coordinate dependence of the ten-dimensional gauge flux components $A_M$, we recover a four-dimensional QCD-like action. In particular, this reduced action contains mass terms of vector mesons, which are related to the Minkowski components of the gauge flux. We calculate the values of these masses and our predictions find good agreement with the experimental values. / Inspiré par le modèle de mécanique chromodynamique (QCD) holographique de Sakai et Sugimoto, nous analysons, dans la limite où N est grand, le spectre mésonique d'un modèle de QCD à température finie à partir de la théorie des cordes correspondante. Après une transformation de dualité T, l'espace-temps de dix dimensions contient N D4-branes et $N_f$ D6/D6-branes et les dimensions enroulées consistent en une variété conique dont la dimension $\psi$ est l'analogue de la dimension enroulée de la géométrie de Sakai-Sugimoto. En utilisant l'approximation de sonde, nous étudions l'action DBI des D6-branes et, en restreignant la dépendance des composantes du flux de jauge $A_M$ de dix dimensions sur les coordonnées Minkowskiennes et $\psi$, nous retrouvons une action à quatre dimensions semblable à celle de QCD. Entre autres, cette action réduite contient des termes de masse de mésons vectoriels lesquels sont reliés aux composantes du flux de jauge. Nous calculons les valeurs de ces masses et nos prédictions sont comparables aux valeurs expérimentales.

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We develop a mesoscopic theoretical framework to study viscoelastic response of block copolymers in the vicinity of their order-disorder transition point. We use it to study orientation selection of lamellar phases of diblock copolymers under oscillatory shears. We examine the effect of hydrodynamics on the relaxation of lamellar phases, and include anisotropic viscous stresses that follow from the uniaxial nature of the phase. We also introduce network viscoelastic effects that model chain entanglements, also made consistent with the symmetry of the phase. A numerical algorithm has been developed to solve the governing equations, which has been implemented on a parallel computer architecture. Simple cases involving the relaxation of small transverse perturbations, or viscoelasticity arising from diffusive relaxation of the order parameter have been investigated, and used to validate the numerical code. We also address the issue of spontaneous orientation selection from an initially disordered state due to an imposed oscillatory shear. In the absence of hydrodynamic coupling, we observe that the so called parallel orientation is selected for small shear frequency and amplitude, crossing over to a perpendicular orientation at higher shear frequencies and amplitudes. Hydrodynamic effects are seen to shift this crossover region. We have also examined the effect of network entanglement at finite frequencies. We find that network entanglement can lead to faster alignment, and that anisotropic network stresses can significantly influence the orientation selection process. / Nous developpons un cadre theorique propre a l'echelle me oscopique dans le but d'etudier la reponse viscoelastique des blocs de copolymeres pres du point de transition entre leur etat ordonne et desordonne. Nous utilisons cette theorie pour e tudier la selection de l'orientation des phases de lamelles des blocs de copolymeres subissant des cisaillements oscillatoires. Nous examinons les effets hydrodynamiques de la relaxation des phases lamellaires et nous incluons les stress visqueux anisotropes, dues a la nature uniaxiale des phases. Nous introduisons aussi les effets viscoelastique relatifs aux r eseaux modelisant l'enchevetrement des chaines dans une approche consistante avec la symetrie des phases. Un algorithme nume rique sous implementation parallele a ete developpe pour resoudre les equations relatives a cette etude. Des cas simples impliquant la relaxation diffuse du parametre relatif a l'ordre ont ete examines et utilises pour verifier le code numerique. Nous adressons aussi la question de la selection de l'orientation spontane d'un etat initialement desordonne due a un cisaillement oscillatoire impose au systeme. Dans l'absence d'interaction hydrodynamique, nous observons que l'orientation denomme e parallele est selectionnee pour des petites frequences et amplitudes de cisaillement mais adopte une orientation perpendiculaire pour de grandes frequences et amplitudes de cisaillement. Les effets hydrodynamiques changent la region de transition. Nous avons aussi examin e l'effet d'enchevetrement du reseau pour des frequences finies. Nous trouvons que l'enchevetrement du reseau mene a un alignement plus rapide et que les stress des reseaux anisotropes peuvent influencer de maniere significative le processus de se lection d'orientation.

In this thesis we study higher spin theories in three dimensional gravity with a negative cosmological constant based on the gauge group SL(N,R)xSL(N,R). First we introduce the topic of semi-classical gravity in three dimensional anti de Sitter space andits conjectured duality with a two dimensional conformal field theory. We study black hole solutions for the case of N=3 characterized by their holonomies around the non-contractible cycles of space-time. The black hole solutions are shown to be gauge equivalent to a BTZ black hole which is charged under a set of U(1) Chern-Simons fields. Nevertheless, depending on the choice of embedding of the gravitational gauge group, the space-time geometry may be non-trivial. We also investigate in detail the physical sensibility of non principal embeddings of the gravitational SL(2,R) in SL(N,R) and we conclude that theonly embedding with a positive definite spectrum is the principal one. / Cette thèse s'intéresse aux théories gravitationnelles couplées à des spins entiers avec une constante cosmologiquenégative, dont l'origine provient de l'étude du groupe de jauge sl_N. La gravitation dans l'espace tridimensionnel anti de Sitter est d'abord décrite de manière semi-classique et la dualité avec la théorie conforme de champs en deux dimensions est ensuite présentée. L'exposition des solutions de la théorie N=3 permet la caractérisation des trous noirs par les propriétés des holonomies autour de boucles non-contractiles. L'invariance de jauge rapproche alors ces solutions aux trous noirs BTZ avec une charge d'un champ Chern-Simons. Néanmoins, la géometrie de l'espace-temps dépend du plongement des symétries gravitationnelles SL(2,R) dans le groupe de jauge SL(N,R). Le spectre des solutions est calculé pour tous ces plongements, et la condition de positivité exclut alors tous les cas sauf le plongement principal.