Observational constraints in extended teleparallel gravity

Abstract

Describing gravity accurately has become one of the lingering problems of modern-day physics. The General Theory of Relativity (GR), as proposed by Einstein, remains the best descriptor we have of the mysterious force, but just like with Newton's theory, GR is running into hurdles that, until now, it cannot overcome. This thesis looks into an alternate formulation of the gravitational theory known as the Teleparallel Equivalent of General Relativity (TEGR) which is equivalent to GR at a background level, and holds promise to provide some sort of explanation towards these problems. Specifically this thesis analyses extensions of TEGR known as f(T) and f(T,B) which seek to provide a deeper explanation towards solving the cosmological constant problem, and attempts to give a better understanding behind the term dark energy. This will be done by constraining cosmological parameters to a few carefully selected models and testing their fit against specific observational data sets in order to examine their performance against the current standard model.