Through theory and observations, it is well established that the universe undergoes accelerated expansion in its history. This accelerated expansion takes place in two different epochs. The first of these is the early epoch of inflation and the second is the current epoch of dark energy domination. Although methods of General Relativity, which is the classical theory of gravity, and Quantum Field Theory, which addresses matter interactions at quantum scales, have guided much of our understanding of the universe, they cannot fully address these epochs of accelerated expansion. In this project the objective is to identify the cosmological degrees of freedom that have a crucial role during inflation and dark energy. It proposes to achieve this goal by studying the ideal case of a spacetime that gives accelerated expansion, using recent methods in holography in order to (i) identify specific deformations from the ideal case that give rise to the cosmological degrees of freedom during inflation and dark energy separately; (ii) explore the generality of these deformations and their cosmological consequences using methods of renormalization group flows; (iii) address deformations in the context of time dependent and space dependent evolution separately to further improve the understanding on the nature of cosmological degrees of freedom. This interdisciplinary project proposes to use the principle of holography from String Theory which can open up a new way of studying cosmological perturbations, especially in the context of dark energy. By focusing on cosmological spacetimes, it will also address the validity of holography in new settings.