Relic Neutrino Search and Cosmic Neutrino Background Mapping

Abstract

This thesis explores the direct detection prospects of the Cosmic Neutrino Background (CNB) and its implications for early Universe cosmology. We develop a theoretical framework for the behavior of nonzero mass neutrinos in a Friedmann-Lemaître-Robertson-Walker universe and calculate the properties of the CNB last scattering surface, showing that massive relic neutrinos originate from closer distances than photons from the CMB. Using constrained cosmological simulations using the 2M++ galaxy survey and the Bayesian Origin Reconstruction from Galaxies (BORG) inference algorithm, we analyze the clustering of relic neutrinos under the influence of large-scale structure formation. We present high- and low-resolution neutrino and dark matter density maps and predict variations in neutrino flux along known superclusters and voids. Our findings support the feasibility of mapping CNB anisotropies with experiments like PTOLEMY, highlighting the influence of gravitational clustering and quantum amplification mechanisms on relic neutrino detection rates. This work contributes to improving the theoretical and simulation groundwork necessary for the first direct observation of the relic neutrino background.