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Статті в журналах з теми "Cosmologia teorica"
Oliveira, Armando Lopes de. "ENSAIO CRÍTICO SOBRE A PRIMEIRA E A SEGUNDA ANTINOMIAS DE KANT." Síntese: Revista de Filosofia 28, no. 91 (June 17, 2010): 169. http://dx.doi.org/10.20911/21769389v28n91p169-187/2001.
Повний текст джерелаSerpa, Nilo Costa. "Lecture Notes on Gauge Theories and Inhomogeneous Cosmologies." CALIBRE - Revista Brasiliense de Engenharia e Física Aplicada 2 (February 1, 2017): 1. http://dx.doi.org/10.17648/calibre.v2.103.
Повний текст джерелаTude de Melo Neto, João Evangelista, and Luis Felipe Xavier Gonçalves. "A RELAÇÃO ENTRE A COSMOLOGIA NIETZSCHIANA E A FILOSOFIA DA NATUREZA DOS ESTOICOS." Revista Ágora Filosófica 1, no. 2 (December 15, 2017): 31–54. http://dx.doi.org/10.25247/p1982-999x.2017.v1n2.p31-54.
Повний текст джерелаCarvalho, Ruy De. "Pensamento único e repetição em Schopenhauer." Voluntas: Revista Internacional de Filosofia 7, no. 1 (June 1, 2016): 105. http://dx.doi.org/10.5902/2179378633755.
Повний текст джерелаNeves, Juliano. "Cosmologia dionisíaca." Cadernos Nietzsche 36, no. 1 (June 2015): 267–77. http://dx.doi.org/10.1590/2316-82422015v3601jn.
Повний текст джерелаNascimento, Luciano, and Anastasiia Melnyk. "Mathematical Formalism in Cosmological Models of Gravity." Semina: Ciências Exatas e Tecnológicas 37, no. 2 (August 16, 2016): 59. http://dx.doi.org/10.5433/1679-0375.2016v37n2p59.
Повний текст джерелаBassani, Douglas. "Análise da interpretação possível do geocentrismo através das tradições de pesquisa." Griot : Revista de Filosofia 23, no. 1 (February 26, 2023): 59–69. http://dx.doi.org/10.31977/grirfi.v23i1.3151.
Повний текст джерелаSUZINA, Ana Cristina. "Por uma teoria circular da comunicação: revisitar e desdobrar a inspiração freireana no pensamento comunicacional latino-americano." Chasqui, Revista Latinoamericana de Comunicación 1, no. 150 (August 21, 2022): 145–60. http://dx.doi.org/10.16921/chasqui.v0i150.4716.
Повний текст джерелаReis, José Alberione dos. "Há uma condição de possibilidade de diálogo entre regimes de conversação e regimes de conhecimentos." Revista de Arqueologia 30, no. 1 (July 3, 2017): 120–43. http://dx.doi.org/10.24885/sab.v30i1.516.
Повний текст джерелаBorges, Luiz. "Cosmologia, religião e discurso Guarani-Mbyá." RUA 6, no. 1 (October 7, 2015): 81. http://dx.doi.org/10.20396/rua.v6i1.8640701.
Повний текст джерелаДисертації з теми "Cosmologia teorica"
CHIOCCHETTA, Caterina. "Indagare la Cosmologia tramite lo spettro di potenza dalle piccole alle grandi scale angolari." Doctoral thesis, Università degli studi di Ferrara, 2022. http://hdl.handle.net/11392/2496466.
Повний текст джерелаAmong the most promising topics in Cosmological investigation we can certainly consider the polarization of the Cosmic Microwave Background (CMB) and the multiwavelength analysis of extragalactic emissions. On one side, CMB polarization allows to better constrain the cosmological parameters and to test the standard model. On the other hand, the study of millimeter and submillimeter data opens the door for investigation of the matter distribution on large scales in order to understand the formation and evolution of the Large Scale Structure. In the first project described in this thesis we present an assessment of the large-scale CMB anomalies in polarisation using the two-point correlation function as a test case. We employ the state of the art of large scale polarisation datasets: the first based on a Planck 2018 HFI 100 and 143 GHz cross-spectrum analysis, relying on SRoll2 processing, and the second from a map-based approach derived through a joint treatment of Planck 2018 LFI and WMAP-9yr. We consider the well-known S 1/2 estimator, which measures the distance of the two-point correlation function from zero at angular scales larger than 60 ◦ , and rely on realistic simulations for both datasets to assess confidence intervals. We find that both datasets exhibit a lack-of-correlation anomaly in local E−modes, similar to the one observed in temperature, which is better constrained by the less noisy Planck HFI 100×143 data, where its significance lies at about 99.5%. The analysis has been carried out with the best datasets currently available at large angular scales, which are however limited by the still significant amount of noise in polarisation observations. This issue will be hopefully overcome by the advent of new data, such as those from LiteBIRD, which are expected to be cosmic variance limited at all scales. In the second project presented in this thesis we developed a tool for data analysis designed for the millimeter and sub-millimeter wavelength datasets. We fit with a unique model data from the South Pole Telescope and the Hershel/SPIRE experiment. Our formalism describes the emission of radio galaxies, the thermal Sunyaev Zeldovich (tSZ) effect, the kinetic Sunyaev Zeldovich (kSZ) effect and the Cosmic Infrared Background (CIB) clustered and Poisson contribution. We use a halo model approach to describe the clustering of dark matter together with a halo occupation distribution model to parametrize the galaxy power spectrum. We fit for the so-called clustering parameters, i.e. minimum mass of the hosting halo and the index regulating the accretion of galaxies in the halo outskirts. We consider two populations of galaxies: early and late-type populations. The key parameter in modelling the tSZ is the hydrostatic mass bias, which strongly depends on cosmology and contains all the uncertainties we have in the determination of the SZ clusters mass. With our analysis we improve the constraints on the clustering parameters of the late-type population, finding that it is hosted in less massive structures with respect to the early-type one. We obtain a minimum mass of 10^12.5 [M/h] and 10^11.4 [M/h] for the early and late-type population respectively, when fitting for SPIRE data. For both datasets we find values of the hydrostatic mass bias, b = 0.57 ± 0.16, higher than those found by Planck, although the amplitude of the tSZ power spectrum obtained with this value of b is in line with the findings of previous SPT analysis. We also kSZ derive a more severe constraint on the amplitude of the kSZ with respect to previous literature, i.e. A(kSZ) < 3.7 at 99% C.L., and investigate its degeneracy with the tSZ-CIB correlation. These results are obtained using the state of the art data available but our tool will be of great utility in the analysis of future datasets, such as the Simons Observatory, CMB-Stage 4 and CONCERTO.
REVERBERI, Lorenzo. "Some Observable Effects of Modified Gravity in Cosmology and Astrophysics." Doctoral thesis, Università degli studi di Ferrara, 2014. http://hdl.handle.net/11392/2388934.
Повний текст джерелаDE, LUCA GIUSEPPE BRUNO. "Non-Supersymmetric Space-Times and Renormalization Group Flows in String Theory." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/257784.
Повний текст джерелаIn this thesis we study solutions of string theories from different perspectives. We start in Chapter 1 with an introduction to the main ideas of string theory, focusing in particular on its low-energy description in terms of supergravity theories. We discuss the main ingredients of the supergravity theories derived from strings and we present their classical solutions corresponding to the physical objects we will use in the rest of the thesis. In Chapter 2 we begin the study of non-supersymmetric backgrounds of string theory, by building explicit eight-dimensional Anti de Sitter (AdS) solutions of massive type IIA supergravity. As is common for non-supersymmetric solutions, we are only able to solve the full set of equations of motion numerically. With these methods, we find AdS_8 solutions with a compact internal space having the topology of a two-sphere, with an orientifold plane (O8) sitting at its equator. In Chapter 3, we extend our study of non-supersymmetric solutions by looking for backgrounds with a positive cosmological constant. In particular, we find numerical four-dimensional de Sitter (dS) solutions of massive type IIA supergravity. Some of these solutions involve the same orientifold plane featuring in the AdS_8 backgrounds, which appears a particular singularity in the supergravity approximation. We analyze this singularity in detail before moving on and studying dS_4 solutions with a different orientifold plane (O6). The appearance of orientifold planes in classical de Sitter solutions of supergravity theories is required in order to evade a famous no-go theorem, which also applies to the AdS_8 solutions we describe in Chapter 2. For this reason, we review it in our particular setting at the beginning of the same chapter. Finally, in Chapter 4 we change our perspective and we use supergravity as a tool to study the physics of the Renormalization Group (RG) flows. In particular, by using known building blocks, we assemble a seven-dimensional gravitational theory and we use it to construct the holographic duals of RG flows between six-dimensional superconformal field theories. Our construction is able to correctly characterize the physics of these RG flows by confirming, from the gravitational point of view, a conjecture on the literature regarding the allowed RG flows between these six-dimensional theories.
Pereira, Thiago dos Santos. "Teoria inflacionária em universos anisotrópicos." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-02032009-151808/.
Повний текст джерелаIn this work we generalize the standard theory of cosmological perturbations to the case of homogeneous and anisotropic universes described by a Bianchi I spacetime metric. As an application of this theory we investigate the predictions of an inflationary anisotropic phase, both at the classical and quantum level. After discussing the evolution of the background spacetime, we solve and quantize the perturbation equations in order to predict the power spectra of the curvature perturbations and gravity waves at the end of inflation. Our results show that the main features of an early anisotropic phase are: (1) a dependence of the spectra on the direction of the modes, (2) a coupling between curvature perturbations and gravity waves, and (3) the fact that the two gravity waves polarisations do not share the same spectrum on large scales. All these effects are significant only on large scales and die out on small scales where isotropy is recovered. Finally, our results depend on a characteristic scale that can, but a priori does not have to, be tuned to some observable scale.
Alves, Márcio Eduardo da Silva. "Cosmologia na teoria de Visser." Instituto Nacional de Pesquisas Espaciais (INPE), 2006. http://urlib.net/sid.inpe.br/MTC-m13@80/2006/12.20.18.30.
Повний текст джерелаThe advent of observational cosmology has led us to conclude that only 4% of whole Universe is composed by known matter (baryons). On the other hand 23% comes from a kind of non barionic dark matter. Moreover the cosmic dynamics is almost fully dominated by the so called dark energy (usually considered a kind of fluid), which corresponds to 73% of the energy density of the cosmos. In the last years, a lot of proposals arises in order to explain such a fluid, while many alternative gravitational theories have been developed aiming to lead us to know more about the physics laws. In this work we review a parametric equation of state of such fluids, which imply on models with accelerated expansion where the cosmological constant is a particular case. We then present the gravitational theory proposed by M. Visser. Such alternative theory assumes that the graviton is massive. In his theory, Visser uses a non-dynamic background metric in order to construct a tensor, which is necessary to take in account a massive graviton. In the non-relativistic limit, the potential is non-Newtonian, it is instead Yukawian. Some studies about orbital motions in the solar system (using this kind of potential) give an upper limit to the graviton mass of mg < 10-54 g. Under the radiative regime, massive gravitons produce dispersive gravitational waves and introduce new polarization states which are not found in the GR. So, future detections of gravitational radiation will offer new tests to GR and to the alternative theories of gravity. In particular, our results show the possibility to constrain the graviton mass through a cosmological model that results from this bimetric theory. Although the graviton has an apparently negligible mass, our aim is to show that the theory may lead us to a consistent cosmological model, which explains the current observational data without dark energy (and maybe without dark matter).
Guzzetti, Maria Chiara. "Observables from inflation: gravitational waves and magnetic fields." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424944.
Повний текст джерелаIl paradigma inflazionario rappresenta una modo affascinante ed elegante di spiegare alcuni cruciali fenomeni cosmologici; inoltre risulta in notevole accordo con le attuali osservazioni cosmologiche. Tuttavia, diversi aspetti della fisica di tale processo risultano ancora oscuri e una prova inequivocabile di tale meccanismo è ancora assente. Dall'altro lato, il meccanismo inflazionario si presenta come soluzione di problemi cosmologici ancora aperti, come l'osservazione di campi magnetici nel mezzo intergalattico. Per studiare in profondità il meccanismo inflazionario, una possibilità è offerta dalla nuova epoca di esperimenti per l'osservazione di onde gravitazionali. La prima parte della tesi è focalizzata su tale aspetto della fisica inflazionaria. Ciascun modello inflazionario predice la produzione di un fondo stocastico di onde gravitazionali (modo tensoriali) dovuti alle fluttuazioni quantistiche del campo gravitazionale. Inoltre, in alcuni scenari, la presenza di ulteriori campi oltre all'inflatone e al campo gravitazionale, genera efficaci sorgenti di onde gravitazionali, attivando la produzione classica. Il segnale di onde gravitazionali inflazionarie si rivela essere una unica e interessante finestra sull'origine e l'evoluzione dell'universo, e la possibilità di investigare la sottostante teoria della gravità. Nella tesi è mostrato il ruolo significativo delle onde gravitazionali primordiali nel testare il meccanismo inflazionario in sè e nel provare diversi aspetti della fisica inflazionaria, sfruttando la validità/violazione di una relazione di consistenza. Essendo le onde gravitazionali inflazionarie, un modo promettente di esplorare diversi aspetto della fisica dell'universo primordiale, è inoltre fornito un quadro aggiornato dello stato attuale e delle prospettive di osservazione dei modi tensoriali inflazionari, con una focalizzazione particolare sulla possibilità di osservazione diretta offerta dagli interferometri laser. Successivamente, sono esposte delle previsioni sulle possibilità offerte dell'interferometro spaziale LISA rispetto al testare la fisica inflazionaria. Nella seconda parte della tesi viene descritto un altro aspetto interessante della fisica inflazionaria, ovvero la possibilità di una significativa magnetogenesi. Le osservazioni di raggi gamma dai blazars indicano la presenza di campi magnetici nel mezzo intergalattico, dove non è presente plasma carico. Questo fatto suggerisce un'origine primordiale di tali campi magnetici. E' interessante notare che il meccanismo inflazionario fornisce un affascinante modo di spiegare la presenza di campi magnetici a scale cosmologiche. In una sezione dedicata, sono mostrati i principali modelli di magnetogenesi inflazionaria. Un aspetto comune di tale modelli è una sovra produzione di perturbazioni di curvatura e tensoriali, rispetto al modello inflazionario di single-field slow-roll. In generale, i limiti osservativi ottenuti da misurazioni di CMB su tali quantità comportano restrizioni significative sulla produzione di campi magnetici associata. Altri limiti sono imposti dal controllo della backreaction dei campi elettromagnetici. In particolare, nella tesi viene considerato il modello proposto da Caprini, in cui ha luogo una magnetogenesi in grado di spiegare le attuali osservazioni dei raggi gamma e di dare inizio al processo di dynamo galattica. Viene calcolata la correzione allo spettro e bispettro degli scalari rispetto al caso di single-field slow-roll, in tale scenario. Il risultato mostra come le restrizioni più forti siano dovute alla non osservazione di un bispettro degli scalari nelle anisotropie della CMB. Ciò nonostante, si conclude che anche quando tali restrizioni vengono prese in considerazione, lo scenario inflazioanrio in esame fornisce una robusta spiegazione dei campi magnetici osservati per una ragionevolmente alta scala di energia dell'inflazione.
Lima, Rodrigo de Castro. "Criação de partículas espinoriais ELKO por efeitos gravitacionais /." Guaratinguetá, 2017. http://hdl.handle.net/11449/149862.
Повний текст джерелаBanca: Elias Leite Mendonça
Banca: Luiz Cleber Tavares de Brito
Resumo: O campo espinorial ELKO associado às partículas de matéria de spin 1/2 e dimensão de massa 1, construídos em um conjunto completo de autoespinores de helicidade dual do operador conjugação de carga, é um canditado a descrever a matéria escura. Devido a sua natureza, possui diversas aplicações cosmológicas. Neste trabalho, o estudo de tais espinores é realizado sob universo de Friedmann-Robertson-Walker plano, homogênio e isotrópico. À luz da Teoria Quântica de Campos em Espaços-Tempo Curvos, com as transformações de Bogoliubov, obteve-se a densidade de partículas criadas em uma métrica modelo de regime assintóticamente plano no passado e no futuro, permitindo-se comparar com soluções exatas presentes na literatura para produção de partículas escalares e férmions de Dirac. Discute- se, também, a compatibilidade do fenômeno de criação de partículas provenientes da Teoria Quântica de Campos em Espaço Curvos com os estudos de Prigogine para descrição deste fenômeno à escala cosmológica, considerando-se um universo termodinamicamente aberto
Abstract: The ELKO spinor field associated with spin 1/2 particles and mass dimension 1, con- structed on a complete set of dual helicity eigenspinors of the charge conjugation operator, is a candidate for describing dark matter. Due to its nature, it has several cosmological applications. In this work, the study of such spinors is performed under a homogenous and isotropic Friedmann-Robertson-Walker universe. In the light of the Quantum Field Theory in Curved Space-Time, with the Bogoliubov transformations, we obtained the density of particles created in a model of asymptotically plane metric in the past and in the future, allowing to compare with exact solutions present in the literature for the production of scalar particles and Dirac fermions. It is also discussed the compatibility of the phenomenon of particle creation from the Quantum Field Theory in Curved Space with the studies of Prigogine to describe this phenomenon at the cosmological scale, considering a thermodynamically open universe
Mestre
Holanda, Rodrigo Fernandes Lira de. "O efeito Sunyaev-Zel\'dovich: teoria e aplicações cosmológicas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/14/14131/tde-13092011-135337/.
Повний текст джерелаThe so-called Sunyaev-Zeldovich effect (SZE) is one of the most promising techniques for cosmological investigations involving galaxy clusters and the cosmic background radiation (CMB). Such an effect is a modification of the Planckian spectrum due to the interaction between the CMB photons and the hot electrons filling the intracluster medium. In this PhD thesis, we constrain some cosmological parameters and investigate the structure of galaxy clusters based on some samples for which the cluster are endowed with simultaneous measurements of SZE and X-ray surface brightness. Two different samples of galaxy clusters are considered, namely: the 25 data compiled by De Fillippis et al. (2005), and the 38 data sample of Bonamente et al. (2006), based on the non-isothermal spherically symmetric model. Initially, we constrain the value of the Hubble parameter, $ H_0 $, by taking into account the different assumptions underlying the galaxy cluster samples in the context of a flat $\\Lambda$CDM model, as well as, for more general cosmologies like the flat XCDM model and $\\Lambda $CDM with curvature. The results depend on the model assumptions and samples. It is also found that a joint analysis involving ESZ/Raios-X of clusters, the baryon acoustic oscillations (BAO) and shift parameter, constitutes an interesting technique for constraining the Hubble parameter and that its value is weekly dependent on the curvature, as well as on the equation of state parameter of the dark energy. By analysing the different samples, we conclude that the elliptical description of the De Filippis et al. (2005) provides the best quality description in comparison with measurements that are independent from galaxy clusters physics. Furthermore, by using galaxy cluster data (SZE/X-ray) and adopting a purely kinematical description for the universal expansion, we obtain that the decelerating parameter is negative with 92 \\% and 72 \\% of the probability by using the Bonamente et al. (2006) and De Filippis et al. (2005) samples, respectively. By simulating future data set, the ability of the ongoing SZE observations to obtain tighter constraints on the expansion history through SZE/X-ray technique is also discussed. On the other hand, since the SZE/X-ray technique for measuring angular diameter distance of clusters depends on the cosmic distance duality relation (DD relation) validity, we investigate the consequences of such a dependence in two distinct ways: (i) we test the consistence between the strict validity of DD relation in the framework of the $\\Lambda$CDM model (WMAP7) and the different assumptions underlying the galaxy cluster geometries, and (ii) we propose a self-consistent and model-independent test for the DD relation by using type Ia supernovae and galaxy clusters data. Finally, for such a test, we also analyse the influence of the different supernovae light curve fitter methods. Our constraints for $H_0$ and the statistical consequences of the distance duality relation provide a new evidence that the true geometry of galaxy clusters is provided by the elliptical form. Such results also reinforce the interest for the observational research involving the Sunyaev-Zeldovich and X-rays from galaxy clusters at moderate and high {\\it redshifts}.
Santos, Renato da Costa. "Topics on cosmological perturbation theory /." São Paulo, 2015. http://hdl.handle.net/11449/135870.
Повний текст джерелаBanca: Robert Brandenberger
Banca: Rogério Rosenfeld
Banca: Nathan Jacob Berkovits
Banca: Luis Raul Weber Abramo
Resumo: Nesta tese a Teoria das Perturbações Cosmológicas é revisada e três tópicos originais, incluídos neste grande ramo da cosmologia teórica, são apresentados. Começamos introduzindo e deduzindo as fórmulas necessárias partindo de primeiros princípios no capítulo 2. Em seguida, no capítulo 3, estudamos em detalhe Teorias Quânticas de Campos em de Sitter que contêm correntes de spin alto. Mostramos que a existência de correntes de spin alto - mesmo em teorias com interação - pode colocar mais vínculos na função de n-pontos, tornando a teoria assintoticamente gaussiana no futuro longínquo. Este resultado pode ser interpretado como o análogo do teorema de ColemanMandula para o espaço-tempo de de Sitter. O capítulo 4 é dedicado a modelos inflacionários conformes com o campo de Higgs fazendo o papel de Inflaton. Modelos com simetria de Weyl e com simetria SO(1, 1) para valores altos da energia são construídos. Verificamos quais as condições necessárias para que se obtenha um valor arbitrário para a razão escalar tensorial, parâmetro que mede a intensidade de ondas gravitacionais primordiais em um dado modelo. Introduzimos também um acoplamento diferente do valor conforme para a interação do campo escalar com o tensor de curvatura. Isto quebra a simetria de Weyl, mas verificamos que existe um forte atrator na direção da linha de Starobinsky. No último capítulo, aplicamos o efeito do 'back reaction' dos modos com comprimentos de onda longo (maiores que o raio de Hubble) em alguns modelos inflacionários e no cenário Ekpyrótico. Checamos se este efeito pode prevenir a inflação eterna nas regiões onde efeitos estocásticos são importantes nestes modelos. Alguns apêndices, com cálculos detalhados, são incluídos no final
Abstract: In this thesis the Theory of Cosmological Perturbations is reviewed and three original topics, that are part of this huge branch of theoretical cosmology, are presented. We start by reviewing and deducing the needed formulas from first principles in chapter 2. After it, in chapter 3, we study in detail Quantum Field Theories in de Sitter spacetime that contain Higher Spin currents. We show that the existence of Higher Spin currents - even in the interacting case - can put further constraints on the n-point function, making it asymptotically gaussian in the far future. This result can be interpreted as the analog of Coleman-Mandula theorem for de Sitter spacetime. Chapter 4 is devoted to conformal inflationary models with the Higgs field playing the role of the Inflaton field. We construct models with a Weyl symmetry and a SO(1, 1) symmetry at high energies. It is verified what are the conditions to get an arbitrary value for the tensor to scalar ratio, which measures the amplitude of primordial gravitational waves in a given model. Also, we introduce a coupling, different from the conformal one, for the scalar field and the curvature tensor. This breaks the Weyl symmetry but we verify that there is a strong attractor towards the Starobinsky line. In the last chapter, we apply the back-reaction effect of long wavelength modes (modes with wavelength bigger than the Hubble radius) in some inflationary models and in the Ekpyrotic scenario. We check if this effect could prevent eternal inflation in the region where stochastic effects are important for these models. Some appendices, with detailed calculations, are also included in the end
Doutor
Sadovski, Guilherme Silva de Araújo. "Cosmologia proveniente de uma teoria de calibre modificada para a gravidade." Niterói, 2017. https://app.uff.br/riuff/handle/1/3950.
Повний текст джерелаMade available in DSpace on 2017-07-04T18:29:04Z (GMT). No. of bitstreams: 1 Guilherme Silva de Araújo Sadovski - Dissertação.pdf: 806650 bytes, checksum: 333998d8c772954dd2891f36903361eb (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O objetivo principal desta dissertação é o de testarmos a consistência em larga-escala de um modelo de gravidade quântica. Este modelo consiste de uma teoria de YangMills para o grupo de calibre SO(m, n) escrita em um espaço-tempo euclidiano quadridimensional. Ao tomarmos o limite infravermelho, a álgebra do grupo SO(m, n) sofre uma contra¸c˜ao de Inönü-Wigner e é deformada na álgebra de Poincaré, quebrando, assim, a simetria de calibre. Como consequências, temos o surgimento das simetrias locais de Lorentz e a identificação dos campos de calibre com a vierbein, e(x), e a conexão de spin, ω(x). A gravidade resultante é uma teoria efetiva tipo-Einstein-Cartan que contém termos de correção ultravioleta e campo de torção propagante. Uma vantagem deste modelo de gravidade induzida é o surgimento natural de uma constante cosmológica gravitacional que, junto com a constante de Newton, G, pode ser calculada perturbativamente. Utilizamos a métrica FLRW e o ansatz de um espaço-tempo riemanniano para demonstramos que esta gravidade efetiva possui o Modelo Cosmológico Padrão como seu limite infravermelho. Além disso, o setor ultravioleta de teoria prevê uma fase de Sitter hiper-acelerada que pode vir a ser associada à inflação e prevê também a presença de matéria exótica no Universo primordial.
Our main go in this thesis is to test the large-scale consistency of a quantum gravity model. This model consists of a Yang-Mills theory with gauge group SO(m, n) written in a four-dimensional euclidean space-time. In the infrared limit, the SO(m, n) algebra undergoes an In¨on¨u-Wigner contraction to Poincaré algebra and the gauge symmetry is broken. As consequence, Lorentz local symmetries arise and the gauge fields can be identified with a vierbein field, e(x), and a spin connection field, ω(x). The resulting gravity is an effective Einstein-Cartan-like theory with ultraviolet correction terms and propagating torsion field. An advantage of this model is the natural appearance of a gravitational cosmological constant that, along with Newton’s gravitational constant, G, can be calculated perturbatively. Making use of the FLRW metric and the ansatz of a riemannian spacetime we demonstrate that this effective gravity has the Standard Cosmological Model in its infrared sector. Furthermore, the ultraviolet regime foresee a hyper-accelerated de Sitter phase that may prove to be inflationary and also foresee the presence of exotic matter in the early Universe.
Книги з теми "Cosmologia teorica"
Gasperini, Maurizio. Lezioni di Cosmologia Teorica. Milano: Springer Milan, 2012. http://dx.doi.org/10.1007/978-88-470-2484-7.
Повний текст джерелаservice), SpringerLink (Online, ed. Lezioni di Cosmologia Teorica. Milano: Springer Milan, 2012.
Знайти повний текст джерелаGasperini, Maurizio. L'universo prima del big bang: Cosmologia e teoria delle stringhe. Roma: F. Muzzio, 2002.
Знайти повний текст джерелаMondadori, ed. Il secolo finale: Perchè l'umanità rischia di autodistruggersi nei prossimi cento anni. Milano: Mondadori, 2004.
Знайти повний текст джерелаOrigen and the life of the stars: A history of an idea. Oxford: Clarendon Press, 1991.
Знайти повний текст джерелаPérez-Mercader, J. Qué sabemos del universo?: De antes del big bang al origen de la vida. Madrid: Editorial Debate, 2001.
Знайти повний текст джерелаPaoli, Marco De. Contro la falsa cosmologia: Per una critica alla legge di Hubble e alla teoria del big bang. Molfetta (BA): Noctua, 2002.
Знайти повний текст джерелаPiękno wszechświata: Superstruny, ukryte wymiary i poszukiwania teorii ostatecznej. Warszawa: Prószyński i S-ka, 2001.
Знайти повний текст джерелаClaudio, Bartocci, ed. L'universo elegante: Superstringhe, dimensioni nascoste e la ricerca della teoria ultima. Torino: Einaudi, 2005.
Знайти повний текст джерелаW, Jackiw Roman, ed. Shelter Island II: Proceedings of the 1983 Shelter Island Conference on Quantum Field Theory and the Fundamental Problems of Physics. Cambridge, Mass: MIT Press, 1985.
Знайти повний текст джерелаТези доповідей конференцій з теми "Cosmologia teorica"
Weide, Alice Taís Dummel. "Tópicos da astronomia que contestam a teoria da Terra plana." In As Astrocientistas - I Encontro Brasileiro de Meninas e Mulheres da Astrofísica, Gravitação e Cosmologia. São Paulo: Editora Blucher, 2022. http://dx.doi.org/10.5151/astrocientistas2021-14.
Повний текст джерелаDale, R., J. A. Morales, D. Sáez, Kerstin E. Kunze, Marc Mars, and Miguel Angel Vázquez-Mozo. "Cosmological vector perturbations in vector-tensor teories of gravitation. CMB anomalies." In PHYSICS AND MATHEMATICS OF GRAVITATION: Proceedings of the Spanish Relativity Meeting 2008. AIP, 2009. http://dx.doi.org/10.1063/1.3141229.
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