Cosmologia e extensão via gravidade de Horndeski.

Abstract

This work investigates Horndeski gravity as an alternative to the standard cosmological model ( -CDM), with an emphasis on alleviating the Hubble tension. Initially, we address the conceptual aspects that formed the basis for the formulation of Einstein’s gravity, along with essential topics in Cosmology. Subsequently, Horndeski gravity is presented, highlighting its mathematical formulation, theoretical properties, and stability conditions. The methodological approach includes the numerical implementation of cosmological equations and parameter fitting to reproduce recent observational data. The results show that the specific non-minimal derivative coupling model within Horndeski gravity can mitigate the Hubble tension by adjusting the scalar potential while maintaining consistency with observational constraints. The analysis of the evolution of energy densities and the Hubble parameter, along with the study of cosmological perturbations, reinforces the stability and feasibility of the proposed model. Therefore, this dissertation contributes to the study of theoretical cosmology, suggesting new possibilities for exploring other sectors of this modified gravity theory in cosmological and astrophysical contexts.