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 19 of 19 for “"General relativity (GR)"”.
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Development of Software to Measure the Gravitational Redshift with RadioAstron
The incompatibility of General Relativity (GR) and quantum theory continues to be a stumbling block in the unification of our understanding of the physical world. Tests of the Einstein Equivalence Principle, lying at the core of GR, are vital to constrain new theories that require departures from …
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Temperature anisotropies: covariant CMB anisotropies and nonlinear corrections
The questions I ask myself are generally all along the lines of "so where did all this structure come from?". I hoped that work in the CMB and its cosmological implications would give me insight into this. It is an adventure that is still young. I began my PhD with an investigation of some formal …
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Symmetries, unitarity and positivity of cosmological effective field theories
… interface between Quantum Field Theory (QFT) and General Relativity (GR). The time dependence of cosmological spacetimes, upon which quantum fields propagate, spontaneously breaks time translation and Lorentz boost invariance. Thus the usual tools of particle physics, which assume full Lorentz …
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From Quantum Information to Cosmic Censorship: Emergent Spacetimes and Their Surfaces
… thesis, we explore classical and semiclassical gravity from the perspective of the AdS/CFT correspondence. We leverage global methods in General Relativity (GR) together with quantum information- and complexity-theoretic properties of the conformal field theory (CFT) dual to obtain novel results …
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Observable signatures of general relativistic dynamics in compact binaries
The effects of general relativity (GR) in astrophysical systems are often difficult to calculate, but they can have important consequences for observables. This thesis considers the impact of previously-ignored GR effects in two different types of compact binary systems. The first is the …
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Gravitational wave cosmology in general relativity and Einstein-scalar-Gauss-Bonnet gravity.
We study systematically gravitational wave (GW) cosmology in both Einstein’s General Relativity (GR) and Einstein-scalar-Gauss-Bonnet (EsGB) gravity. We first investigate the spacetime singularities of plane GWs in GR and find that only few of them are free of spacetime singularities. In …
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Studies of strong-field gravity : testing the black hole hypothesis and investigating spin-curvature coupling
Observations of gravitational systems agree well with the predictions of general relativity (GR); however, to date we have only tested gravity in the weak-field limit. In the next few years, observational advances may make it possible for us to observe motion in the strong field for the first time. …
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Numerical modelling of gravitational wave sources in general relativity
The first direct detection of gravitational waves (GWs) from a black-hole (BH) binary, GW150914, by the advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) detectors in 2015 heralded a new era in GW physics. Since then, over 90 compact binary merger events have been detected by the …
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Gravitational collapse, compact objects and gravitational waves in General Relativity and modified gravity
Since the upgrade of the two LIGO Detectors it has been an exciting time for General Relativity (GR) research, as soon after they were upgraded to advanced status GW150914, the first gravitational wave signal from the inspiral and merger of two black holes was detected. The following consistent …
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Exploring gravity
Gravitation is the dominant influence in most astrophysical interactions. Weak-field interactions have been extensively studied, but the strong-field regime remains largely unexplored. Gravitational waves (GWs) are an excellent means of accessing strong-field regions. We investigate what we can …
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Effects of resonances and spin-curvature coupling in extreme mass ratio inspirals
Since Einstein proposed the theory of general relativity (GR) as a theory of gravity, it has passed all experimental checks and tests. Until recently, all of these tests have been done in the weak gravity limit. The first test of strong-field GR came just a few months ago, when the LIGO …
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Probes of strong-field gravity
… this thesis, I investigate several ways to probe gravity in the strong-field regime. These investigations focus on observables from the gravitational dynamics, i.e. when time derivatives are large: thus I focus on sources of gravitational waves. Extreme mass-ratio inspirals (EMRIs) can be very …
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Gravitational Effective Field Theories and Black Hole Mechanics
General Relativity (GR) has been immensely successful at predicting gravitational phenomena at the energy scales we have observed thus far. However, we know GR will lose its predictive power at sufficiently high energy scales due to its nonrenormalizability. Therefore, we should think of GR as the …
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Testing General Relativity with the next generation of cosmological surveys
… of the Universe is conceptually considered the great burdensome issue in theoretical physics (cosmological problem) dubbed dark energy (DE) problem. In general relativity (GR) framework view point, there are two ways to explain where this acceleration might originate from; this riddle might …
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Spectral-Timing Observations of Disk-Jet Coupling in Black Hole X-ray Binaries
… ideal laboratories to ultimately test Einstein's general relativity (GR) in the strongest gravity regime in the Universe. High-fidelity GR tests require a precise knowledge of the physical environments in which particles move. Two biggest challenges there are how close to the event horizon …
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PROBING THE NATURE OF COMPACT OBJECTS: SCATTERING, TIDES AND QUASINORMAL MODES
The LIGO-VIRGO-KAGRA (LVK) collaboration has detected 90 confirmed gravitational-wave (GW) events and nearly 200 confident triggers across four observational runs. Coalescing black-hole (BH) and neutron-star (NS) binaries are primary GW sources, offering the unique possibility to probe the nature …
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On electromagnetic observables from supermassive black hole accretion flows
… the hole and the warped spacetime predicted by general relativity. This dissertation describes a series of projects aimed at understanding and identifying signatures of the physical quantities relevant to the black hole–jet connection in both observational and theoretical contexts. I start with …
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Uncovering gravitational wave signatures of modified theories of gravity and exotic matter
The observation of the first gravitational-wave (GW) event almost a decade ago opened a new promising window to our scientific endeavours in understanding the deepest mysteries of our Universe and its history. Using the foundations of general relativity (GR), we are now in the position of being …
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Numerical Modelling of the Dynamics and Gravitational Radiation of Compact Binaries in General Relativity
General relativity (GR), published in 1915 by Albert Einstein, is the modern description of gravity. GR poses that gravitational physics should be described by matter fields existing in a curved space described by differential geometry. The Newtonian gravitational force is viewed as a fictitious …