Exploring new windows into fundamental physics at high energies

This thesis explores two windows into fundamental physics: (1) textbf{Cosmic inflation}: By considering inflation as a window to the physics at high energies and to quantum gravity, we study two inflationary models. In one model, we study the quantum corrections for Starobinsky's inflationary model cite{Starobinsky:1980te}, in which we investigate how are cosmological observables affected by quantum effects. Our results show that these observables are significantly affected, but they still agree with observations. We stress that the significant deviations from Starobinsky's inflationary model can be used to study and constrain the quantum loop effects during inflation. The other model is a curvaton model, in which the quantum effects induce a non-minimal coupling to gravity. We find that the non-minimal coupling could use to tune the scalar power spectral index $n_s$ and the power spectrum $P_zeta$. (2) textbf{Emergent gravity}: Statistical laws of black hole suggest that gravity is not fundamental but instead of an emergent phenomenon. One such theory was proposed by Verlinde~cite{Verlinde:2016toy}. In order to test the validity of his theory, we propose two tests of the theory: the perihelion advancement of a planet and the microlensing. We find that Verlinde's theory can be probed by the next generation of experiments.