In a time of thriving Gravitational Wave physics, we study Black Hole Quasi-Normal Modes emitted in the post-ringdown phase of merger events. By using Boundary Effective Field Theoretical methods,...Show moreIn a time of thriving Gravitational Wave physics, we study Black Hole Quasi-Normal Modes emitted in the post-ringdown phase of merger events. By using Boundary Effective Field Theoretical methods, we search for modifications to General Relativity in the strong-field limit, for scalar as well as gravitational field perturbations. Going beyond General Relativity, Black Holes are predicted to produce echoing signals, for which we characterise observational parameters, by searching for leading order Boundary Conditions near the Black Hole horizon. For a scalar field, we discuss a parity symmetric and a shift symmetric configuration, while for a gravitational field, parity and diffeomorphism symmetry are implemented. The diffeomorphism symmetric Boundary Condition oddly seems to mix modes. Given the intimate relationship between Effective Field Theory and renormalisation techniques, we also comment on recent first principle arguments that have been brought up regarding the supposed impossibility of echo observation. We find that these arguments over-interpret a regularisation cut-off. From our perspective, the arguments still have merit, but do not form the no-go theorem that it seems to. In the end, only observation can give the decisive answer on the existence of Black Hole echoes.Show less
In this thesis a detailed description of the KKLT scenario is given as well as as a comparison with later papers critiquing this model. An attempt is made to provide a some clarity in 17 years...Show moreIn this thesis a detailed description of the KKLT scenario is given as well as as a comparison with later papers critiquing this model. An attempt is made to provide a some clarity in 17 years worth of debate. It concludes with a summary of the findings and possible directions for further research.Show less
Parton distribution functions (PDFs) are vitally important for high energy physics calculations. Vast amounts of experimental evidence have shown that scattering processes involving nuclei cannot...Show moreParton distribution functions (PDFs) are vitally important for high energy physics calculations. Vast amounts of experimental evidence have shown that scattering processes involving nuclei cannot be solved using the free-nucleon formalism of perturbative QCD and therefore, a separate empirical determination of the nuclear modification of PDFs is necessary. Because the shape and size of nuclear modification are theoretically unmotivated, the NNPDF collaboration uses a neural network to achieve a model-independent parametrisation. In this thesis, we include new Z boson production data from pPb collisions into the NNPDF framework and examine its impact on the quality of the fit. We will also discuss the phenomenological implications of prompt photon production data in pPb collisions.Show less
We will discuss non-local solutions to some of the problems of the standard model of cosmology, L cold dark matter (LCDM), focusing on two models of gravity and their applications to cosmology. The...Show moreWe will discuss non-local solutions to some of the problems of the standard model of cosmology, L cold dark matter (LCDM), focusing on two models of gravity and their applications to cosmology. The first comes from modifying the Einstien-Hilbert action by including an m2R 1 2 R term and the second by including an m2 1 R term. Both models posses self-accelerating solutions. I will demonstrate that their background cosmology is consistent with data, and testable primarily through the equation of state of our universe’s effective stress-energy tensor. At the perturbative level, these models have more galaxy clustering and weak lensing, so they are be highly testable using up coming cosmological surveys. My contribution to this work is the perturbation theory of the m2 1 R model and the recovery of these results for the m2R 1 2 R model.Show less
