Cosmological signatures of fundamental physics

Cosmology;Large-scale structures;Neutrinos;Galaxy surveys;Self-interacting dark matter

Banerjee, Arka

关键词: Cosmology;    Large-scale structures;    Neutrinos;    Galaxy surveys;    Self-interacting dark matter;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/98101/BANERJEE-DISSERTATION-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This thesis deals with the study of the cosmological signatures of certain aspects of fundamental physics, and how cosmological observables can be used to constrain properties of fundamental particles. Over the past decades, increasingly precise measurements in cosmology have become powerful probes of fundamental physics - for example, the inference of dark matter and dark energy from cosmological observations remain the most significant evidence of new physics beyond the Standard Model of particle physics. Another example is the cosmological scalar-to-tensor ratio, which can potentially differentiate different models of inflation and other early Universe theories.Determining the absolute mass scale of neutrinos is an interesting problem in particle physics, and can shed light on the mass generation mechanism for neutrinos, which, in turn, can tell us about physics beyond the Standard Model. To fully exploit the signatures of massive neutrinos on cosmological observables, one needs to perform accurate simulations. In this thesis, we explore a new method for performing neutrino simulations, which overcome the shortcomings of previous methods which were employed. From these simulations, we identify an observable which is very sensitive to the neutrino mass - the clustering of cosmological voids on large scales. We also forecast how well the neutrino masses and thermal ``dark radiation'' models can be constrained in future cosmological surveys using their effect on various observables in these surveys, such as the clustering of galaxies, galaxy-galaxy lensing, and cosmic shear.Cosmological observables can also be used to constrain the properties of Dark Matter itself. While Dark Matter has traditionally been considered a collisionless fluid, there has been recent interest in self-interactions of dark matter. We consider a special form of self-interactions in this thesis - where the interactions are elastic but anisotropic. We develop the formalism and methods to simulate these interactions, and study the signatures of these interactions on the properties ofdark matter halos.