Late-time constraints on matter-coupled models of teleparallel gravity

Abstract

The theory of gravitation was revolutionised by Einstein in 1915 with his theory of General Relativity (GR). Despite its successful predictions, there are several flaws with GR. The main goal of the dissertation is to address two of GR’s flaws - the dark energy problem and the growing Hubble tension, particularly its late-time component. This will be done by looking into an alternative theory of gravitation known as Teleparallel Gravity (TG) which using certain limits leads to the Teleparallel Equivalent of General Relativity (TEGR). The dissertation will analyse novel modifications of TEGR known as f(T, Θ), where there is a non-minimal coupling between the matter sector and gravity. The analysis will be performed using a Markov Chain Monte Carlo (MCMC) algorithm coupled with late-time data coming from cosmic chronometers and supernovae explosions. The algorithm will constrain the cosmological parameters and measure how well the models fit the late-time cosmological data. Finally, the results will be compared to the Lambda Cold Dark Matter (LCDM) model which is currently the standard model of cosmology. The study’s findings could have significant implications on further modifications of TEGR by considering the viability of these novel models of cosmology.