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Full-Text Articles in Cosmology, Relativity, and Gravity

Critical Phenomena In The Gravitational Collapse Of Electromagnetic Dipole And Quadrupole Waves, Maria F. Perez Mendoza Jan 2021

Critical Phenomena In The Gravitational Collapse Of Electromagnetic Dipole And Quadrupole Waves, Maria F. Perez Mendoza

Honors Projects

We report on critical phenomena in the gravitational collapse of electromagnetic waves. Generalizing earlier results that focused on dipole electromagnetic waves, we here compare with quadrupole waves in axisymmetry. We perform numerical simulations of dipole and quadrupole wave initial data, fine-tuning both sets of data to the onset of black hole formation in order to study the critical solution and related critical phenomena. We observe that different multipole moments have different symmetries, indicating that the critical solution for electromagnetic waves cannot be unique, at least not globally. This is confirmed in our numerical simulations: while dipole data lead to a …


Cosmological Gravitational Waves: Refining A General Rule Of Thumb For Reheating, David Zhou Jan 2021

Cosmological Gravitational Waves: Refining A General Rule Of Thumb For Reheating, David Zhou

Honors Projects

There are predictions for cosmological gravitational wave backgrounds from reheating based on various models. But, these predictions do not address the question of how an observed spectrum relates back to an unknown model or parameter. Given this problem, we have numerically and analytically investigated a variety of chaotic inflation models and their gravitational wave spectra. In doing so, we found a power law relation between gravitational wave peak frequency and an underlying chaotic inflation parameter. We found a two-class amplitude puzzle related to how strongly a matter producing field is coupled to the inflaton. We estimated the parameter describing how …