Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (p. 113-122).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 81-85).

The fuzzball model of a black hole is an attempt to resolve the many paradoxes and puzzles of black hole physics that have revealed themselves over the last century. These badly behaved solutions of general relativity have given physicists one of the few laboratories to test candidate quantum theories of gravity. Though little is known about exactly what lies beyond the event horizon, and what the ultimate fate of matter that falls in to a black hole is, we know a few intriguing and elegant semi-classical results that have kept physicists occupied. Among these are the known black hole entropy and the Hawking radiation process.

Στη διατριβή αυτή θα μελετήσουμε μονότονες ποσότητες στα πλαίσια συνδυασμένων γεωμετρικών ροών. Πιο συγκεκριμμένα, εστιάζοντας την προσοχή μας στη περίπτωση των σολιτονίων Ricci, ως περιβάλλοντες χώρους, θα θεωρήσουμε λύσεις της εξίσωσης θερμότητας ολοκληρωμένες πάνω σε εμβαπτισμένες υποπολλαπλότητες οι οποίες εξελίσσονται χρονικά με τη ροή μέσης καμπυλότητας. Επιπρόσθετα, στη περίπτωση του συνδυασμού αντίστροφης ροής Ricci, ροής μέσης καμπυλότητας, όταν ο περιβάλλων χώρος είναι Kahler, η λύση της αντίστροφης εξίσωσης θερμότητας, ολοκληρωμένη πάνω στην υποπολλαπλότητα αποτελεί μονότονη ποσότητα. / -

Made available in DSpace on 2015-03-03T11:52:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-03Bitstream added on 2015-03-03T12:06:59Z : No. of bitstreams: 1 000798812.pdf: 406540 bytes, checksum: 7793d5a1f9bfbe358b5dde7a7418b448 (MD5) / O século passado é considerado como a era das Teorias Quânticas de Campos. Desta forma, neste trabalho, forneceremos todos os detalhes de uma descoberta teórica inesperada de uma partícula de matéria de spin 1/2 com dimensão de massa 1. Esses espinores recebem o nome de ELKO, o qual vem do acrônimo alemão Eigenspinores des Ladungskonjugationsoperators, e são fundamentados em um conjunto completo de autoespinores de helicidade dual do operador conjugação de carga. O ELKO pertence a um subgrupo do grupo completo de Lorentz. Portanto, a lei de transformação entre suas componentes não é dada pela simetria de paridade, e desta maneira não satisfaz a equação de Dirac. Intrinsicamente nas somas de spin para o ELKO aparece um termo que quebra a simetria de Lorentz, levando então à apreciação da Very Special Relativity, que nada mais é do que um subgrupo do grupo de Lorentz, cuja álgebra deixa as somas de spin invariantes ou covariantes. Pela razão do propagador do ELKO ser o mesmo de Klein-Gordon a menos de um fator, a lagrangiana associada é a do campo escalar, por esta razão o ELKO é dotado de dimensão de massa 1 / The last century is considered as the era of Quantum Field Theories. Thus, in this work, we provide all the details of an unexpected theoretical discovery of a matter particle spin 1/2 endowed with mass dimension 1. These spinors are the so called ELKO, which comes from the German acronym Eigenspinores des Ladungskonjugationsoperators, based on a complete set of a dual helicity eigenspinors of the charge conjugation operator. ELKO belongs to a subgroup of the full Lorentz group. Therefore, the law of transformation between its components is not given by the parity symmetry, and thus it does not satisfies the Dirac equation. It appears, intrinsically in the spin sums a Lorentz symmetry breaking term, then it will be better analysed within the Very Special Relativity, which is a subgroup of the Lorentz group, whose algebra leaves the spin sums invariant or covariant under transformations. Since the ELKO propagator is the same of Klein-Gordon propagator apart from a term, than the associated lagrangian is the scalar field one, for this reason ELKO is endowed with mass dimension 1

Nós estudamos a competição entre a instabilidade de Pomeranchuk no canal de spin com momento angular l=1 e uma interação atrativa, favorecendo a formação de um par de Cooper. Achamos, numa aproximação de campo médio, uma forte supressão da instabilidade de Pomeranchuk via supercondutividade. Além disso, identificamos uma fase supercondutora metaestável com características semelhantes ao estado FFLO. Um líquido de Fermi é, com exceção de uma dimensão, um estado muito estável da matéria. Por outro lado dois tipos de instabilidades, relacionadas com interações atrativas, são conhecidas: Instabilidades Pomeranchuk e supercondutora. As instabilidades Pomeranchuk ocorrem na presença da interação de dois corpos contendo uma forte componente atrativa no canal de espalhamento para frente com momento angular definido. No contexto da teoria de Landau, a instabilidade ocorre quando um ou mais parâmetros admensionais de Landau nos canais de spin ou carga, adquirem altos valores negativos. As instabilidades Pomeranchuk no setor de carga quebram a simetria de rotação. Em particular, uma instabilidade em alguns canais produz uma deformação elipsoidal na superfície de Fermi. / We study the competition between a Pomeranchuk instability in the spin channel with angular momentum l = 1 and an attractive interaction, favoring Cooper pair formation. We find, at mean-field approximation, that superconductivity strongly suppress the Pomeranchuk instability. Moreover, we have found a metastable modulated superconducting phase with similar characteristics of the FFLO state. A Fermi liquid is, except in one dimension, a very stable state of matter. At least two types of instabilities, related with attractive interactions, are known: Pomeranchuk and superconducting instabilities. Pomeranchuk instabilities occur in the presence of two-body interactions containing a strong attractive component in the forward scattering channel with a definite angular momentum. In the context of Landau theory, the instability sets in when one or more dimensionless Landau parameters in the charge or spin channel, acquire large negative values. Pomeranchuk instabilities in a charge sector spontaneously break rotational symmetry. In particular, an instability in the some channels produces an ellipsoidal deformation of the Fermi surface.

Orientador: Nathan Jacob Berkovits / Banca: Horatiu Stefan Nastase / Banca: Vladimir Demyanovich Pershin / Resumo: A presente dissertação trata-se de uma revisão sobre amplitudes MHV na teoria de Yang-Mills e em sua extensão maximalmente supersimétrica. A demonstração da fórmula geral para tais amplitudes é dada no terceiro capítulo. Uma vez que o formalismo de twistors se apresenta como um interessante arcabouço teórico para o estudo de tais amplitudes, uma discussão sobre o mesmo e considerada, bem como sua extensão supersimétrica. Ao final, o cálculo de quatro e cinco pontos para amplitudes MHV em teoria de supercordas é apresentado. Para tal, foi utilizada a prescrição fornecida por Berkovits e Maldacena em [11] / Abstract: In the present work, we have provided a review about MHV amplitudes in Yang- Mills and maximally supersymmetric Yang-Mills theory. A proof of MHV formula was given in the third chapter. Since twistor formalism provides an interesting framework to study such amplitudes, a discussion about it is also considered as well as its supersymmetric extension. At the end, we have computed MHV four-point and ve-point gluon tree amplitudes in superstring theory, using a prescription given by Berkovits and Maldacena [11] / Mestre

This thesis investigates applications of the gauge/gravity duality to strongly coupled quantum field theories. After a review of the duality and of correlators and transport in quantum systems, we present our results on second-order non-conformal hydrodynamics. We derive new Kubo formulae for five second-order transport coefficients in non-conformal relativistic fluids. We then apply these Kubo formulae to a class of non-conformal holographic fluids at infinite coupling. We find strong evidence that the Haack-Yarom identity, known to relate second-order coefficients in conformal holographic fluids at infinite coupling, continues to hold in holographic fluids without conformal symmetry: Within our class of models, we prove that it still holds when leading non-conformal corrections are taken into account, and we show numerically that it is also obeyed beyond leading order. This provides further evidence that the identity may be a universal feature of strongly coupled fluids. Next, we present our results on magnetic spin impurities in strongly correlated systems. We build a holographic two-impurity Kondo model, identifying the inter-impurity interaction as double-trace deformation. Our numerical results for the phase diagram suggest a quantum phase transition between a trivial phase with uncorrelated spins and no Kondo screening, and a non-trivial phase with anti-ferromagnetic correlations and simultaneous Kondo screening. Computing the spectrum in the single-impurity case, we observe Fano resonances, which at low temperatures we identify with the Kondo resonance.

No description available.

The Standard Model of particle physics is believed to be only the low energy limit of a more fundamental theory. In order to determine its range of validity, a major part of theoretical and experimental efforts in physics is dedicated to precision tests of the Standard Model. Lattice QCD is a non-perturbative, first-principles approach to Quantum Field Theory. It plays an important role in flavor physics by providing calculations of non-perturbative strong interaction contributions to weak processes involving quarks. Measurements of hadronic quantities can be used to constrain the Standard Model as well as theories Beyond the Standard Model. The first part of this thesis contains theoretical developments regarding non-perturbative renormalization. A new renormalization scheme, RI/mSMOM, for fermion bilinear operators in QCD at non-vanishing quark mass is presented. In order to investigate the properties of the mSMOM scheme, an explicit one-loop computation in perturbation theory using dimensional regularization is performed. Numerically, vertex functions are generated on the lattice, with an appropriate projector, based on the RI/SMOM scheme and the renormalization factors are extracted. Quantities measured include renormalization of the axial current ZA, required to renormalize the axial current entering the computation of the decay constant and the renormalization of the bag parameter. The second part of this report focuses on flavor physics phenomenology on the lattice. It presents results of the first run of the RBC/UKQCD charm project with (2+1)-flavor Domain Wall fermions. Observables and matrix elements are measured on lattices with Iwasaki gauge action. There are two ensembles at the physical point with inverse lattice spacings 1.73 and 2.36 GeV and a third finer ensemble at 2.76 GeV as well as four other auxiliary ensembles with smaller volumes and heavier pion masses which are used to perform the continuum extrapolations. The quantities measured in the region of the charm quark mass are meson masses, decay constants, the matrix element of the OV V +AA operator, the neutral D-meson mixing parameter B and the SU(3) breaking ratio ξ.