Closer Look at Dark Energy

The universe is in a period of accelerated expansion; and the observational evidence such as supernova of Ia type, Cosmic Microwave Background radiation (CMB) and Baryon Acoustic Oscillations (BAO) confirm this accelerating expansion [1-3]. Despite the great number of observational evidence, the responsible mechanism for this accelerating expansion is still unknown, and thus several models have been proposed for this phenomenon [4-18]. The simplest proposed model in the general relativity is a cosmic model with a dominant component that is considered as a fluid with negative pressure and constant density [8] (means Dark Energy component). In this book, we consider effects of Dark Energy content on the universe. Accordingly, structure of discussions in the present book was on four chapters as follows: chapter 1: Dark Energy, Motivation and Candidates, chapter 2 : The Equivalence Principle Applicability Boundaries, Measurability, Gravity and Dark Energy Problem, chapter 3 : The Behaviors of a Candidate for Dark Energy from ur-Higgs Boson , and chapter 4 : Non-equilibrium Evolution of Quantum Fields During Inflation and Late Accelerating Expansion .However, I hope this collection of context will be useful for readers to understand more accurately the dark energy idea.