Orientadores: Patricio Anibal Letellier Sotomayor e Kyoko Furuya / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-11T10:44:32Z (GMT). No. of bitstreams: 1 Silva_MarceloZimbres_M.pdf: 810192 bytes, checksum: 16b4f94ccf4183c0371eac2b660a72f3 (MD5) Previous issue date: 2008 / Resumo: Para estudar de forma completa a precessão de um giroscópio em órbita, revisamos a dedução das equações de Papapetrou, em particular, para mostrar que em uma aproximação de partícula teste essas equações implicam o transporte de Fermi-Walker do spin. Para estudar as correções devidas a oblaticidade de um corpo central na precessão do spin, fizemos uma revisão da teoria dos multipolos relativísticos focados nas definições de Geroch-Hansen e de Thorne. Usamos todos esses conceitos para estimar as correções multipolares na precessão de Lense-Thirring, em especial, encontramos uma fórmula exata para a precessão em termos de dois escalares, as partes real e imaginária do potencial de Ernst. Em uma aproximação linear para o campo gravitacional, escrevemos nossa fórmula em termos dos multipolos de Thorne. Para estimar essas correções usamos alguns modelos conhecidos para a métrica do planeta Terra e comparamos nossos resultados com outros trabalhos / Abstract: To study the precession of an orbiting gyroscope we review the theory of the Papapetrou equations and show that they imply the Fermi-Walker transport law. We review also the theory of relativistic multipole moments, specifically the definitions of Geroch-Hansen and Thorne, to describe non-spherical bodies in general relativity. For stationary axially symmetric spacetimes we find a simple expression for the Lense-Thirring precession in terms of the Ernst potential. This expression is used to compute, in the weak field approximation, the major non-spherical contributions to the precession of a gyroscope orbiting the Earth. We use some known models for the earth metric to estimate the contributions and compare our results with some previously known ones / Mestrado / Física / Mestre em Física

This thesis details the design and construction of an experiment to measure the radial distribution of laser gain in a cylindrical Helium-Neon laser gain tube. This distribution is important as it can effect the transverse mode structure of a running ring laser. Earlier theoretical models of the distribution were not supported by high quality experimental data and fail to take into account some physical processes. A resolution of 8 parts per million in gain and 50 μm in radial position has been achieved. Gain distributions have been measured and are shown to be well modeled by a 0th order Bessel function with first roots at the tube walls and a central dip depending on excitation power; except for the region very near to the tube walls where a very rapid increase in gain has been observed. Hydrogen has been identified by spectroscopic analysis as the primary constituent of gas contamination and cause of the long term reduction in gain of large ring lasers. Additional work has been done to detect a proposed non-classical Lense-Thirring field around a spinning lead superconductor. It was found that any effect is at least 20 times smaller than predicted. Techniques and tools for data acquisition programming have been reviewed focusing on difficulties with coupling of user interface and application logic, monolithicity, difficulties with scripting and algorithm implementation.

This thesis details the design and construction of an experiment to measure the radial distribution of laser gain in a cylindrical Helium-Neon laser gain tube. This distribution is important as it can effect the transverse mode structure of a running ring laser. Earlier theoretical models of the distribution were not supported by high quality experimental data and fail to take into account some physical processes. A resolution of 8 parts per million in gain and 50 μm in radial position has been achieved. Gain distributions have been measured and are shown to be well modeled by a 0th order Bessel function with first roots at the tube walls and a central dip depending on excitation power; except for the region very near to the tube walls where a very rapid increase in gain has been observed. Hydrogen has been identified by spectroscopic analysis as the primary constituent of gas contamination and cause of the long term reduction in gain of large ring lasers. Additional work has been done to detect a proposed non-classical Lense-Thirring field around a spinning lead superconductor. It was found that any effect is at least 20 times smaller than predicted. Techniques and tools for data acquisition programming have been reviewed focusing on difficulties with coupling of user interface and application logic, monolithicity, difficulties with scripting and algorithm implementation.

Made available in DSpace on 2015-03-03T15:15:26Z (GMT). No. of bitstreams: 1 NoeliaSS_DISSERT.pdf: 603590 bytes, checksum: 0c1bbc3243a667550fdf0a46772b336d (MD5) Previous issue date: 2011-07-01 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The so-called gravitomagnetic field arised as an old conjecture that currents of matter (no charges) would produce gravitational effects similar to those produced by electric currents in electromagnetism. Hans Thirring in 1918, using the weak field approximation to the Einsteins field equations, deduced that a slowly rotating massive shell drags the inertial frames in the direction of its rotation. In the same year, Joseph Lense applied to astronomy the calculations of Thirring. Later, that effect came to be known as the Lense- Thirring effect. Along with the de Sitter effect, those phenomena were recently tested by a gyroscope in orbit around the Earth, as proposed by George E. Pugh in 1959 and Leonard I. Schiff in 1960. In this dissertation, we study the gravitational effects associated with the rotation of massive bodies in the light of the Einsteins General Theory of Relativity. With that finality, we develop the weak field approximation to General Relativity and obtain the various associated gravitational effects: gravitomagnetic time-delay, de Sitter effect (geodesic precession) and the Lense-Thirring effect (drag of inertial frames). We discus the measures of the Lense-Thirring effect done by LAGEOS Satellite (Laser Geodynamics Satellite) and the Gravity Probe B - GPB - mission. The GPB satellite was launched into orbit around the Earth at an altitude of 642 km by NASA in 2004. Results presented in May 2011 clearly show the existence of the Lense-Thirring effect- a drag of inertial frames of 37:2 7:2 mas/year (mas = milliarcsec)- and de Sitter effect - a geodesic precession of 6; 601:8 18:3 mas/year- measured with an accuracy of 19 % and of 0.28 % respectively (1 mas = 4:84810??9 radian). These results are in a good agreement with the General Relativity predictions of 41 mas/year for the Lense-Thirring effect and 6,606.1 mas/year for the de Sitter effect. / O denominado campo gravitomagn?tico surgiu como uma antiga conjectura de que correntes de mat?ria (sem cargas) produziriam efeitos gravitacionais an?logos aos produzidos pelas correntes el?tricas no Eletromagnetismo. Hans Thirring em 1918, usando a aproxima??o de campo fraco para as equa??es de campo de Einstein, deduziu que uma casca massiva girando lentamente arrasta os referenciais inerciais no sentido de sua rota??o. No mesmo ano Joseph Lense aplicou na Astronomia os c?lculos de Thirring. Posteriormente, este efeito ficou conhecido como efeito Lense-Thirring. Juntamente com o efeito de Sitter, esses fen?menos foram recentemente testados atrav?s de girosc?pios em ?rbita em torno da Terra, uma antiga proposta feita por George E. Pugh em 1959 e por Leonard I. Schiff em 1960. Nesta disserta??o, estudamos os efeitos gravitacionais associados ? rota??o de corpos massivos ? luz da teoria da Relatividade Geral de Einstein. Com essa finalidade, desenvolvemos a aproxima??o de campo fraco para a Relatividade Geral e obtemos os v?rios efeitos gravitacionais associados: atraso gravitomagn?tico dos rel?gios (gravitomagnetic time-delay), efeito de Sitter (precess?o das geod?sicas) e o efeito Lense-Thirring (arraste dos referenciais inerciais). Discutimos as medidas do efeito Lense- Thirring do sat?lite LAGEOS (LAser GEOdynamics Satellite) e da miss?o "Sonda Gravidade B"(Gravity Probe B - GPB). O sat?lite da GPB foi lan?ado em ?rbita em torno da Terra a uma altitude de 642 km pela NASA em 2004. Resultados apresentados em maio de 2011 mostram claramente a exist?ncia do efeito Lense-Thirring - um arraste dos referenciais inerciais de 37; 2 7; 2 msa/ano (msa = milisegundo de arco)- e do efeito de Sitter - uma deriva geod?tica de 6:601; 8 18; 3 msa/ano - com precis?o de 19% e de 0,28% respectivamente (1 msa = 4; 848 10?9 radiano). Esses resultados est?o em bom acordo com os valores previstos pela teoria da Relatividade Geral que s?o de 41 msa/ano para o efeito Lense-Thirring e 6.606,1 msa/ano para o efeito de Sitter

La gravitation expérimentale a connu des développements spectaculaires ces vingt dernières années en partie grâce aux développements de la physique atomique. A l'aide de techniques de refroidissement sophistiquées, il est possible d'exploiter le comportement ondulatoire de la matière. L'interférométrie atomique est devenue une méthode de fabrication d'horloges et de senseurs inertiels parmi les plus précis et la condensation de Bose-Einstein permet<br />l'observation de phénomènes quantiques macroscopiques. Dans cette thèse, nous explorons quelques applications possibles des ondes de matière pour les expériences de gravitation en champ faible. En première partie, nous développons des outils génériques pour la description théorique des expériences en relativité générale. Nous les appliquons dans la seconde partie: nous calculons la sensibilité des interféromètres à ondes de matière à l'effet Lense-Thirring, puis aux ondes gravitationnelles, et nous les comparons aux interféromètres laser. Enfin nous calculons la probabilité de changement d'état d'une cavité à onde de matière en interaction avec une onde gravitationnelle.

Les jets sont des phénomènes d’éjection collimatée de plasma magnétisé. Ces ph́énomènes liés à l’accrétion d’un disque sur un objet central, sont relativement répandus dans l’univers : les environnement des étoiles jeunes (objets Herbig-Haro, étoiles T Tauri), des binaires X, des sursauts gamma et les noyaux actifs de galaxies... Les jets extra-galactiques sont issus des trous noirs super-massifs au centre de galaxies telles que les quasars ou les radiogalaxies. Ils sont caractérisés par leur taille, leur puissance et la vitesse du plasma.Les jets extragalactiques sont étudiés dans de ce travail de thèse, même si les outils et méthodes développés peuvent être utilisés pour les binaires X et les micro-quasars. Nous poserons en particulier les questions des mécanismes de lancement, d’accélération et de collimation de ces écoulements. Nous traiterons également de la source énergétique à l’origine de l’écoulement qui peut atteindre une puissance de l’ordre de 10^47 erg.s−1.Le liens avec l’accrétion, la proximité de la base des jets avec le trou noir central, les vitesses d’écoulement observées dans certains jets, montrent que le traitement de ces questions doit inclure les effets de la relativité générale. Nous étudierons donc des solutions de la décomposition 3+1 des équations de la magnéto-hydrodynamique en métrique de Kerr. Nous nous appliquerons au développement d’un modèle d’écoulement méridional auto-similaire avec un traitement consistant du cylindre de lumière. Ce modèle pouvant s’appliquer à la fois au jet et à l’accrétion. Nous explorons les mécanismes d’accélération et de collimation des solutions produites. Nous calculerons des solutions de l’écoulement entrant dans l’horizon et de l’écoulement sortant à l’infini incluant des termes d’injection de paires. Le rôle du mécanisme de création de paires et des processus d’extraction de l’énergie du trou noir sera exploré. / Jets are collimated ejection phenomena of magnetized plasma. These phenomena related to the accretion of a disk on a central object, are relatively common in the universe: the environment of young stars (Herbig- Haro Objects, T Tauri stars...), X-ray binaries, Gamma-ray-bursts, and active galactic nuclei... Extragalactic jets come from super-massive black holes in the center of galaxies such as quasars or radiogalaxies. They are characterized by their size, their power and velecity of the plasma.Extragalactic jets will be the subject of studies in this thesis work, although the tools and methods developed can be used for X-ray binaries and microquasars. In particular, we will ask questions about the mechanisms of launching, accelerating and collimating these flows, but also about the energy source at the origin of the flow that can reach a power in the order of 10^47erg.s−1.The links with the accretion, the proximity of the jet base to the central black hole, flow velocities observed in some jets, show that the treatment of these issues must include the effects of general relativity. We will therefore study solutions of the 3+1 decomposition of magneto-hydrodynamic equations in Kerr metric. We will apply ourselves the development of a meridional self-similar magnetized flow model with a consistent treatment of the light cylinder effect. This model can be applied to both spine jet and accretion. We explore the mechanisms of acceleration and collimation of the obtained solutions. We will calculate solutions of the incoming flow in the horizon and the outgoing flow reaching infinity including injection terms. The role of the pair creation mechanism and the processes of extracting energy from the black hole are explored.