Entropy In The Present And Early Universe: New Small Parameters And Dark Energy Problem

Abstract

It is demonstrated that entropy and its density play a significant role in solving the problem of the vacuum energy density (cosmolog- ical constant) of the Universe and hence the dark energy problem. Taking this in mind, two most popular models for dark energy - Holo- graphic Dark Energy Model and Agegraphic Dark Energy Model - are analyzed. It is shown that the fundamental quantities in the first of these models may be expressed in terms of a new small dimensionless parameter. It is revealed that this parameter is naturally occurring in High Energy Gravitational Thermodynamics and Gravitational Holog- raphy (UV-limit). On this basis the possibility of a new approach to the problem of Quantum Gravity is discussed. Besides, the results ob- tained on the uncertainty relation of the pair ”cosmological constant - volume of space-time”, where the cosmological constant is a dynamic quantity, are reconsidered and generalized up to the Generalized Un- certainty Relation