Dynamics Of Dark Energy-dark Matter Interactions

There has been conclusive observational evidence in astronomy indicating that our universe has entered an epoch of accelerated expansion. Within the frame of the stan-dard cosmological model, this implies that the universe is driven by a new mysterious dark energy, which is unlike any form of common matter or energy and counters the attractive force of gravity. Dark Energy is one of the most important discoveries in cos-mology with profound implications in physics. Science magazine listed Dark Energy as the first among the top ten science problems of our time.The most part of this PhD thesis endeavors to seek the basic properties of Dark Energy. Starting from the inertia of Dark Energy, we study the dynamics of the universe when dark energy interacting with dark matter and explore the possible ways to detect such interaction through astronomical observations.This thesis is organized as follows:In Chapter 1, we will introduce the basic equa-tions of motion for the interacting system. In Chapter 2, we will introduce the dark energy and dark matter interacting model and discuss the dynamical stability of such model. In chapter 3, we will explore the possibilities to detect such interaction in CMB and LSS. In chapter 4, we will introduce the influence of the interaction in structure formation and galaxies number counts. In chapter 5, we will discuss the DGP model with Gauss-Bonnet curvature correction. In the last chapter, we will summarize our results and list future directions of research.