Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 66 for “"De Sitter"”.
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Aspects of quantum field theory, holography and de Sitter
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-02-04 without embargo terms
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Perturbative Quantum Gravity and Yang-Mills Theories in de Sitter Spacetime
… we calculate the Feynman propagators of the Faddeev- Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge. In the third part we investigate the physical equivalence of covariant Wightman graviton two-point function with the physical graviton two-point …
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Physical and Geometrical Aspects of De Sitter Interior of A Gravastar
… reported in this thesis is the gravastar model for physical black holes.</p>
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Numerical Construction of Gravitational Solutions in Asymptotically Anti-de Sitter Spacetimes
Asymptotically anti-de Sitter (AdS) spacetimes display intriguing phenomena which have recently sparked increasing interest in the research of gravitational solutions in these spaces. Considerable motivation stems from gauge/gravity duality, which is a conjecture relating classical gravity with a …
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Stationary Anti-de Sitter Black Hole Solutions in and out of Equilibrium
… cosmological constant. The AdS/CFT correspondence has caused an upsurge in studying anti-de Sitter (AdS) space, and under this duality, the study of classical black holes corresponds to studying thermal states of very strongly coupled conformal field theories (CFTs) — an extremely challenging …
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Linear waves on higher dimensional Schwarzschild black holes and Schwarzschild de Sitter spacetimes
… Schwarzschild black holes and Schwarzschild de Sitter spacetimes. In the first part of this thesis two decay results are proven for general finite energy solutions to the linear wave equation on higher dimensional Schwarzschild black holes. I establish uniform energy decay and improved …
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Violating the Weak Cosmic Censorship Conjecture in Asymptotically Anti-de Sitter Space-Times
… in both cases the space-time curvature can be made to grow without bound in a region visible to distant observers by imposing sufficiently violent boundary conditions on the metric or gauge field. In the electromagnetic case, this only happens at zero temperature, and we present a new numerical …
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Lorentz Invariant Spacelike Surfaces of Constant Mean Curvature in Anti-de Sitter 3-Space
… </em>= <em>c</em><em> </em>in the anti-de Sitter 3-space H<sup>3</sup><sub>1</sub>(<em>−c</em><sup>2</sup>) of constant curvature <em>−c</em><sup>2</sup>. In particular, I construct Lorentz invariant spacelike surfaces of constant mean curvature <em>c</em><em> </em>and maximal Lorentz …
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Lorentzian Poisson homogeneous spaces, quantum groups and noncommutative spacetimes
El objetivo de esta Tesis Doctoral es el estudio de ciertas deformaciones cuánticas de los grupos cinemáticos Lorentzianos (Poincaré y (anti-)de Sitter), sus espacios homogéneos cuánticos asociados, y algunas de sus consecuencias físicas. En particular, se construye el espacio no conmutativo de …
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Decay for quasilinear wave equations on cosmological black hole backgrounds
This thesis studies the decay and stability of linear and quasilinear wave equations of Schwarzschild--de~Sitter $(M,\Lambda)$ and Kerr de Sitter $(a,M,\Lambda)$ black hole backgrounds, where $a,M,\Lambda$ are respectively the rotation parameter of the black hole, the mass of the black hole and the …
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Infinite derivative gravity : a ghost and singularity-free theory
… at later times. To this end, an infinite derivative extension of relativity is introduced, with the gravitational action derived and the non-linear field equations calculated, before being linearised around both Minkowski space and de Sitter space. The theory is then constrained so as to …
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Infinite Derivative Gravity : a finite number of predictions
Ghost-free Infinite Derivative Gravity (IDG) is a modifed gravity theory which can avoid the singularities predicted by General Relativity. This thesis examines the effect of IDG on four areas of importance for theoretical cosmologists and experimentalists. First, the gravitational potential …
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The gravitational field in a fluid sphere of uniform invariant density according, to the theory of relativity ; Note on de Sitter ̕Universe ; Note on the theory of pulsating stars
… (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1927.
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The Phase of the Cosmological Wavefunction
… and locality form a vital foundation for our descriptions of fundamental physics. Their implications for particle physics are well established, through, for instance, the spin–statistics theorem, the optical theorem, and the CPT theorem. In contrast, their role in quantum interactions in …
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The trial of the holographic principle
We present an introduction to ideas related to the holographic principle in the context of the well-established duality between classical gravity and conformal fluid dynamics. Foundations of relativistic hydrodynamics, conformal invariance, and geometry of anti-de Sitter spaces are discussed. We …
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Obstacles to realizing Quintessence from String Theory
… we analyze the construction of quintessence models by flux compactification of type IIB string theory. We focus on Kähler moduli as candidates for the quintessence field and briefly comment on other approaches. The large hierarchies required for simultaneously describing quintessence and the …
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Causality and unitarity in the early universe
… universe, with its high energy scales, provides a unique opportunity to explore new physics. Insights into this are encoded in the correlation functions of primordial perturbations, observable through the CMB and LSS anisotropies. To maximize these insights, it is essential to adapt tools …
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Conformal Properties of Spacetime
… timelike curves λ, ν in the same domain of outer dependence, there exists a future directed timelike curve from λ to ν. Penrose showed that this property is equivalent to the entirety of future null infinity being contained in the timelike future of every point in past null infinity. We will …
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Some Numerical and Phenomenological Studies in Loop Quantum Cosmology
… to large macroscopic universes at late times, a detailed study of the robustness of the quantum bounce for a generic class of initial condition has so far been missing due to severe computational challenges. In the first part of this dissertation, we develop the Chimera scheme, an efficient …
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Wave Equations on Curved Spacetimes
… where there are stably trapped null geodesics that have zero energy relative to an observer at infinity. We give a heuristic argument as to why this may lead to a non-linear instability, which can be seen at the linear level by studying the wave equation. We calculate the quasinormal …
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