Esta dissertação visa realizar um estudo acerca dos modelos de mundo brana no contexto proposto por Randall e Sundrum. O trabalho focaliza as perturbações de spin 0 no espaço-tempo de Kerr tomado como um mundo brana 4-dimensional. Para isso apresentamos os principais aspectos da Relatividade Geral de Einstein, bem como perturbações em métricas que descrevem buracos negros. Fizemos uma revisão dos modelos de Randall-Sundrum, suas motivações e tentativas de descrever buracos negros na brana. Por m a perturbação escalar da corda negra em rotação (Kerr-Randall-Sundrum) e o fenômeno de super-radiação são analisados. / This dissertation aims at studying the braneworld models in the context proposed by Randall and Sundrum. The focus is on the spin-0 perturbations in the Kerr space-time as a 4- dimensional braneworld. The work deals the main aspects of Einstein General Relativity as well as perturbations of black holes metrics. We also review the Randall-Sundrum models and their motivations and attempts to describe braneworld black holes. In the end the Kerr-Randall-Sundrum black string scalar perturbation and superradiance are obtained.

Dentro da área Ensino de Ciências identificamos diversos trabalhos que defendem a utilização de obras literárias no contexto de ensino-aprendizagem. Nesta pesquisa pretendemos contribuir com o diálogo entre a literatura e o ensino de ciências, utilizando referenciais da linguística e da linguagem na análise de três romances de ficção, escritos por físicos: -Sonhos de Einstein? de Alan Lightman (1992); -Tau Zero? de Poul Anderson (1970) e -O Tempo e o Espaço do Tio Albert? (1989) de Russel Stannard. O elemento motivador de nosso trabalho surge a partir das possibilidades da inserção da Física Moderna no ensino de física, assim como a possibilidade da interface entre Física e Literatura em sala de aula. Entretanto, como veremos adiante, o diálogo entre a física do início do século XX e as obras literárias é presente na obra de diversos autores, portanto havia a necessidade de um recorte temático que possibilitasse um recurso educacional para o ensino de física moderna. Dessa forma, a Teoria da Relatividade configura-se como uma teoria da física moderna que permite essa pesquisa por conta: do entendimento da TER como um fenômeno cultural; do diálogo histórico entre a Teoria da Relatividade e a Literatura; da necessidade de novos recursos para o ensino de TER e da exploração da TER para além dos conceitos. Os romances mencionados são caracterizados por tratar dos fenômenos inerentes à TER tanto em nível conceitual, quanto epistemológico. Portanto sua utilização no ensino de Física possibilita a discussão das esferas conceituais, sócio-histórica e filosófico-epistemológica em sala de aula. Para a análise da instância da produção e do discurso externo às obras, utilizaremos a análise de discurso derivada dos trabalhos de Mikhail Bakhtin, quanto à estrutura interna do texto, utilizamos a semiótica estruturalista de A.J. Greimas. A utilização da semiótica e da análise do discurso para analisar um romance a ser levado em sala de aula, possibilita identificar elementos textuais que auxiliem na construção dos conceitos junto aos estudantes. As diferentes percepções dos personagens se relacionam com as próprias ansiedades que a sociedade verifica na ciência, que dependendo da forma como é divulgada possui conotações eufóricas ou disfóricas. Além disso, a instância da produção do texto, que identifica o seu público-alvo e o discurso ideológico, possibilita a reflexão por questões sócio-históricas inerentes à ciência e ao papel do cientista. Quanto ao ensino de TER, tal análise, propicia uma reflexão sobre a abordagem dos conceitos e fenômenos relativísticos, norteando as novas visões sobre espaço e tempo que a teoria propõe. / It is possible to identify in Sciences Education several studies that advocate the use of literary works in the context of teaching and learning. In this research, we intend to contribute to the dialogue between literature and science teaching, using references from linguistics and language in the analysis of three fictional novels, written by physicists: \"Einstein\'s Dreams\" by Alan Lightman (1992); \"Tau Zero\" Poul Anderson (1970) and \"Time and Space of Uncle Albert\" (1989) by Russell Stannard. Our work motivation comes from the possibility of integration of modern physics in physics education, as well as the possibility of the interface between physics and literature in the classroom. However, as we shall see, the dialogue between the physics of the early twentieth century literary works and literature is present in the work of many authors, so there was need for a thematic focus that would enable an educational resource for teaching modern physics. Thus the special theory of relativity is configured as a theory of modern physics that enables this research because of: the understanding of the STR as a cultural phenomenon, the historical dialogue between the Theory of Relativity and Literature, the need for new resources for teaching STR and explored this theory beyond the concepts. The novels mentioned are characterized by treating the phenomena inherent in STR at both the conceptual and epistemological. Therefore its use in the teaching of physics allows the discussion of conceptual spheres, socio-historical and philosophical-epistemological classroom. For the analysis of the fictional text, we use benchmarks for Discursive Studies. For instance the analysis of speech production and external to the works, we use discourse analysis derived from the works of Mikhail Bakhtin, the internal structure of the text, use structuralist semiotics of AJ Greimas. The use of semiotics and discourse analysis to analyze a novel to be brought into the classroom enabling to identify textual elements, what helps in constructing the concepts together with students. As different perceptions of the characters relate to their own anxieties that society finds in science, depending on how it is disclosed has connotations euphoric or dysphoric. Furthermore, the instance of text production, identifying your target audience, as well as the ideological discourse, allows the reflection of socio-historical issues related to science and the scientific role. As for teaching STR, this analysis provides a reflection on the approach to relativistic concepts and relativistic phenomena, guiding the new views on space and time that the theory proposes.

Diese Arbeit präsentiert ein modernes Michelson-Morley Experiment, welches genauere Grenzwerte für Testparameter liefert, die eine Verletzung der Lorentzinvarianz modellieren. Die Messung setzt einen oberen Grenzwert für eine Anisotropie der Lichtgeschwindigkeit im Bereich von dc/c ~10^-16. Das Experiment vergleicht die Frequenzen zweier optischer Hoch-Finesse Resonatoren, wobei einer dieser Resonatoren kontinuierlich auf einem Drehtisch rotiert. Um die Eigenfrequenzen der Resonatoren abzufragen, werden die Frequenzen zweier Nd:YAG-Laser auf die Resonatoren stabilisiert. Die relative Frequenzstabilität auf der Zeitskala einer Tischdrehung (~45s) liegt bei ~1x10^-14, limitiert durch das thermische Rauschen der Resonatorspiegel. Die Messung erstreckt sich über einen Zeitraum von einem Jahr, wobei mehr als 10^5 Tischumdrehungen eingehen. Ausführlich werden die systematischen Effekte und ihre Unterdrückung auf Signalamplituden unter 1 Hz dargestellt. Im Vergleich zu vorhergehenden Messungen konnten diese systematischen Effekte um einen Faktor 10 bis 100 reduziert werden. Zwei verschiedene Testtheorien wurden herangezogen, um ein Signal für eine Anisotropie der Lichtgeschwindigkeit als Folge einer Verletzung der Lorentzinvarianz zu modellieren: eine die Lorentzinvarianz verletzende Erweiterung des Standardmodells und die Testtheorie von Robertson, Mansouri und Sexl. Es wird eine Analyse der Daten im Rahmen beider Testtheorien präsentiert, und Grenzwerte auf die relevanten Parameter werden bestimmt. Diese Grenzwerte schränken eine Anisotropie der Lichtgeschwindigkeit im Bereich von 10^-16 ein, d.h. etwa 10 mal genauer als die Ergebnisse vorangegangener Messungen. Schließlich wird ein Ausblick auf einen verbesserten Aufbau gegeben, welcher neue Resonatoren zum Einsatz bringt, und es werden erste verbesserte Resultate präsentiert. Damit steht der Weg offen für eine Langzeit-Messung, welche die Grenze für eine Anisotropie der Lichtgeschwindigkeit bis in den Bereich von dc/c~10^-17 drücken wird. / This thesis presents a modern Michelson-Morley experiment, which provides improved limits on test parameters that model a violation of Lorentz invariance in electrodynamics. The measurement sets an upper limit on an anisotropy of the speed of light at a level of dc/c~10^-16. The experiment compares the resonance frequencies of two optical high-finesse cavities, one of them continuously rotating on a turntable. To read out their resonance frequencies, two Nd:YAG lasers are frequency-stabilized to these cavities. On the timescale of a turntable rotation (~45s), a relative frequency stability of ~1x10^-14 is achieved, limited by thermal noise of the cavity mirrors. The measurement extends over one year and includes ~10^5 rotations. The systematic effects compromising the measurement are described in detail, together with the measures that have been taken to suppress systematic effects below 1 Hz. This is a reduction by a factor of up to 100 as compared to preceding experiments. Two different test theories are applied to derive a signal for an anisotropy of the speed of light as a consequence of a violation of Lorentz invariance: a Lorentz violating extension of the standard model and the test theory by Robertson, Mansouri and Sexl. An analysis of the data within these two test models is presented, and limits on the relevant test parameters are deduced. These limits restrict an anisotropy of the speed of light at a level of 10^-16, which is a factor of ten more stringent as compared to results of previous such measurements. Finally, an outlook on an improved setup with new cavities and and first results from this setup are presented. This setup should allow for another order of magnitude improvement of the experiment''s sensitivity within a following long-term measurement aiming for the dc/c ~10^-17 level of accuracy.

A discrete formalism for General Relativity was introduced in 1961 by Tulio Regge in the form of a piecewise-linear manifold as an approximation to (pseudo-)Riemannian manifolds. This formalism, known as Regge Calculus, has primarily been used to study vacuum spacetimes as both an approximation for classical General Relativity and as a framework for quantum gravity. However, there has been no consistent effort to include arbitrary non-gravitational sources into Regge Calculus or examine the structural details of how this is done. This manuscript explores the underlying framework of Regge Calculus in an effort elucidate the structural properties of the lattice geometry most useful for incorporating particles and fields. Correspondingly, we first derive the contracted Bianchi identity as a guide towards understanding how particles and fields can be coupled to the lattice so as to automatically ensure conservation of source. In doing so, we derive a Kirchhoff-like conservation principle that identifies the flow of energy and momentum as a flux through the circumcentric dual boundaries. This circuit construction arises naturally from the topological structure suggested by the contracted Bianchi identity. Using the results of the contracted Bianchi identity we explore the generic properties of the local topology in Regge Calculus for arbitrary triangulations and suggest a first-principles definition that is consistent with the inclusion of source. This prescription for extending vacuum Regge Calculus is sufficiently general to be applicable to other approaches to discrete quantum gravity. We discuss how these findings bear on a quantized theory of gravity in which the coupling to source provides a physical interpretation for the approximate invariance principles of the discrete theory. / by Jonathan Ryan McDonald. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

O impacto que estruturas algébricas podem exercer em teorias físicas e bem ilustrado pela Mecânica Quântica, onde os números complexos são inquestionavelmente a escolha mais adequada para desenvolver a teoria. A Relatividade Geral pseudo-complexa avalia a possibilidade da interação gravitacional assumir sua descrição mais natural quando construída tendo como base os números pseudo-complexos, que consistem em uma das três possibilidades de números complexos abelianos com uma unica unidade imaginária. Esse conjunto numérico e dotado de elementos não nulos cujo produto e zero, tais números recebem o nome de zeros generalizados ou divisores de zero. A presença de zeros generalizados permite a introdução de um princípio variacional modificado do qual um termo adicional, ausente na Relatividade Geral, emerge nas equações de campo. Esse termo adicional e interpretado como uma energia escura, cuja origem física está relacionada com flutuações no vácuo. A inclusão desse efeito e legítima pois flutuações no vácuo a priori devem gravitar como qualquer outra forma de energia. Das equações de campo podemos resumir a principal ideia conceitual da teoria, na Relatividade Geral pseudo-complexa massa não apenas curva o espaçotempo como também e capaz de alterar a estrutura do espaço-tempo ao redor da massa. As diferenças com relação a Relatividade Geral se manifestam em situações físicas extremas, no regime de campos gravitacionais intensos. Como aplicação analisamos sob o ponto de vista teórico um objeto compacto exótico composto por matéria escura fermiônica. / The impact that algebraic structures can exert on physical theories is well illustrated by Quantum Mechanics, where complex numbers are unquestionably the most appropriate choice to develop the theory. Pseudo-complex General Relativity evaluates the possibility that the gravitational interaction acquires its most natural description when constructed upon pseudo-complex numbers, which consist of one of the three possibilities of abelian complex numbers with a single imaginary unit. This numerical set is endowed with nonzero elements whose product is zero, such numbers are called generalized zeros or divisors of zero. The presence of generalized zeros allows the introduction of a modi ed variational principle from which an additional term, absent in General Relativity, emerges in the eld equations. This additional term is interpreted as a dark energy, whose physical origin is related to vacuum uctuations. The inclusion of this e ect is legitimate because a priori vacuum uctuations must gravitate as any other form of energy. From the eld equations we can summarize the main conceptual idea of the theory, in pseudo-complex General Relativity mass not only curves spacetime but also is able to change the structure of the spacetime around the mass. The di erences with respect to General Relativity are manifested in extreme physical situations in the regime of intense gravitational elds. As an application we analyze from the theoretical point of view an exotic compact object composed of fermionic dark matter.

No description available.

Trapped ions in linear Paul traps are largely isolated from interaction with the environment. This property of trapped ions make them a primary choice for quantum technology. Over the last decade, trapped atomic ions in linear radio frequency Paul traps have shown to be an important tool to implement quantum algorithms. The scalability of linear ion traps is required to handle large numbers of qubits, in order to implement useful quantum computation. Advance micro-fabrication technology allows the realisation of scalable ion traps. Further developments of micro-trap designs, for the purpose of scalable quantum technology, requires inter-disciplinary investigations of ion traps. Micro-scale ion trap designs typically require a versatile experimental setup. The first part of this thesis describes such an experimental setup including a chip bracket that can host macroscopic ion traps as well as advanced symmetric and asymmetric ion trap chips with up to 90 control electrodes. The system provides versatile optical access for both type of traps and the vacuum chamber is designed in a way so the ion traps can be replaced within a short amount of time. To test the working of the setup, a macroscopic ion trap with an ion-electrode distance of 310±10 μm is used to trap ytterbium ions (Yb+). The trap is characterised by measuring the heating rate, (n•), and spectral noise density SE(ω). A photoionisation technique is used to ionise the different isotopes of Yb in our trap. Isotope selective photoionisation requires exact measurements of 1So↔1P1 transition for the different Yb isotopes. A technique to measure these resonant frequencies is described. This technique works by observing and aligning fluorescence spots and by using this technique, the 1So↔1P1 transition frequencies for stable isotopes of Yb were measured with an accuracy of 60 MHz. These new measured transition frequencies for stable Yb isotopes differ from previously published work by 660 MHz. Furthermore, this technique can also be used to obtain the transition frequencies at different laser-atomic beam angles, typical for non-perpendicular laser-atomic beam angles. The second part of this thesis discusses the optimisation of surface trap geometries as they are being used to implement scalable ion trap designs which consist of a large number of trapping zones. The trap depth in surface traps is low compared to symmetric traps of similar dimensions. How to optimise the trap geometry to achieve maximum trap depth for a given ion height above the trap electrodes, is discussed. Fast and adiabatic ion shuttling operations in one dimension as well as ion separation and recombination processes are important for many quantum information implementations. The maximum speed of separation of trapped ions for adiabatic shuttling operations depends on the secular frequencies, the trapped ion experiences in the process. It will be shown how such ion trap structures have to be designed for fast ion separation process and linear shuttling. Numerical results of adiabatic shuttling operations for trapped ions in such trap structures are also presented.

The subject of this thesis is the description of quantum black holes as a way to probe quantum gravity. Scenarios of a lower Planck scale make quantum gravity experimentally approachable, therefore a theoretical framework is needed in order to be able to probe quantum gravitational effects. We present a field theoretical formalism for the treatment of quantum black holes and their interactions with particles of the Standard Model. We examine the properties and assumptions governing quantum black holes and develop a methodology to examine their behavior using quantum field theory language. We apply our formalism in several different cases and calculate the cross sections for the production of quantum black holes. We use our results to gain phenomenological insights to quantum gravity, such as the derivation of bounds for the Planck mass from Standard Model processes. The distinction between a continuous and a discrete mass spectrum, for a quantum black hole, is discussed and the relevant cross sections presented. Finally, we use quantum black holes as a gateway to supersymmetry and calculate the branching ratios for the decay of quantum black holes into supersymmetric particles.

La première partie de cette thèse traite des théories de gravité massive. L'étude de ces théories a connu un regain d'intérêt depuis la découverte de l'accélération de l'expansion de l'univers, car elles pourraient expliquer cette dernière sans avoir à recourir à une constante cosmologique. La découverte, en 2010 d'une théorie cohérente de gravité massive, dite dRGT, a ouvert un vaste et prometteur champ d'investigation. Dans cette thèse nous déterminons, dans une formulation métrique et covariante, la linéarisation autour d'espace-temps arbitraires de ces théories, et de leur extension bimétrique. Ce travail nous permet ensuite de compter par une méthode lagrangienne le nombre de degrés de liberté qui se propagent. La seconde partie de cette thèse s'inscrit dans le cadre des ondes gravitationnelles en relativité générale et porte plus précisément sur la dynamique de systèmes binaires d'objets compacts. Ce travail est important dans la perspective de leur détection par les détecteurs interférométriques d'ondes gravitationnelles terrestres et spatial. Nous étudions le problème de la dynamique de systèmes binaires d¿objets compacts en relativité générale, à l¿aide de la méthode d'approximation dites des développements post-newtoniens (PN). Nous dérivons les équations du mouvement à l'ordre $4$PN en coordonnées harmoniques. Nous utilisons une méthode basée sur une action de Fokker adaptée au formalisme post-newtonien, en dérivant notamment les effets de sillage d'onde qui apparaissent à $4$PN. / The first part of this thesis deals with massive gravity theories. There has been a renewal of interest in these theories since the discovery of the acceleration of the expansion of the universe, because they could explain it without having to resort to a cosmological constant. The discovery in 2010 of a coherent theory of massive gravity, named dRGT, has opened a vast and promising field of investigation. In this thesis we determine, in a metric and covariant formulation, the linearization around arbitrary backgrounds of these theories and their bimetric extension. This result then allows us to count with a Lagrangian method the number of degrees of freedom that are propagating. The second part of this thesis concerns gravitational waves in general relativity and especially the dynamics of coalescing compact binary systems. This work is important in view of their detection by interferometric detectors, both terrestrial and spacial. We study the dynamics of compact binary systems in general relativity, using the approximation method based on post-Newtonian developments (PN). We derive the equations of motion to $4$ PN order in harmonic coordinates. We use a method based on a Fokker action adapted to the post-Newtonian formalism, in particular deriving the tail effects appearing at $4$PN.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-08-15T17:16:32Z No. of bitstreams: 1 PDF - Bruno Barros Camêlo.pdf: 1453825 bytes, checksum: 0c755892d9dbe76fb2ec46bbaa59aad2 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-08-17T15:30:31Z (GMT) No. of bitstreams: 1 PDF - Bruno Barros Camêlo.pdf: 1453825 bytes, checksum: 0c755892d9dbe76fb2ec46bbaa59aad2 (MD5) / Made available in DSpace on 2016-08-17T15:30:31Z (GMT). No. of bitstreams: 1 PDF - Bruno Barros Camêlo.pdf: 1453825 bytes, checksum: 0c755892d9dbe76fb2ec46bbaa59aad2 (MD5) Previous issue date: 2014-10-08 / In physics is very familiar employment of vectors. These can be seen, the geometric point of view, as straight segments oriented. However, certain quantities are better represented by other objects with geometrical features than with vectors. Such objects are represented by fragments of oriented planes, which cannot be determined by vectors, unless we are in three dimensional space. Geometric or Clifford algebra can be treated as a generalization of vector algebra, and consists of a powerful formalism for the physical description of nature. Thus, we propose in this work, to build strategies to introduce the Clifford algebra as modeler physical concepts of the Theory of Special Relativity and from the modeled concepts, develop educational material for teaching physics in the light of the conception of learning Ausubel. / Na Física é muito familiar o emprego de vetores. Estes podem ser vistos, pelo ponto de vista geométrico, como segmentos de reta orientados. No entanto, certas grandezas ficam mais bem representadas por outros objetos com características geométricas do que com os vetores. Tais objetos são representados por fragmentos de planos orientados, os quais não podem ser determinados por vetores, a menos que estejamos no espaço tridimensional. A álgebra geométrica ou de Clifford pode ser tratada como uma generalização da álgebra vetorial, e consiste em um poderoso formalismo para a descrição física da natureza. Assim, propomos nesse trabalho,construir estratégias para introduzir a álgebra de Clifford como modelador de conceitos físicos da Teoria da Relatividade Restrita à luz da concepção Ausubeliana da aprendizagem para organizar os conceitos dentro de um modelo cognitivo.