Energy Conditions of Built-In Inflation Models inf(T)Gravitational Theories

Gamal G L Nashed

doi:10.1155/2015/687940

Abstract

We examine the validity of energy conditions of built-in inflation models inf(T)gravitational theories. For this purpose, we formulate the inequalities of energy conditions by assuming the flat and nonflat Friedmann-Robertson-Walker (FRW) universe. We find the feasible constraints on the constants of integration and evaluate their possible ranges graphically for the consistency of these energy conditions for flat, closed, and open universes. We constrain the constants of integration for flat space-time from the inflation epoch while the closed and open universe constants are constrained from late universe.

Highlights

Recent observations show that the present expansion of our universe is accelerating [1,2,3,4,5,6,7,8,9,10,11,12]
This means that dark fluid has equation of state (EoS) very close to −1 which represents an important point in favor of a cosmological constant-like representation of the dark energy (DE)
The cosmological constant appears as the vacuum energy density, which has to be included in gravity theory, as the vacuum effect [13]

Summary

Introduction

Recent observations show that the present expansion of our universe is accelerating [1,2,3,4,5,6,7,8,9,10,11,12]. We are going to review some derived solutions of FRW in the frame of f(T) In these cosmological applications the universe is taken as homogeneous and isotropic in space, which directly gives rise to the tetrad given by Robertson [75]. In the case of spatially flat FRW universe, k = 0, the solution of continuity equation (12) gave the scale factor in the form [76]. In the case of the closed FRW universe, k = +1, the solution of the continuity equation gave the scale factor in the form [76]. In the case of the open FRW universe, k = −1, the solution of the continuity equation (12) gave the scale factor in the form [76]. To study the energy conditions of the above models, we are going to give a brief review of the energy conditions

Brief Review of Energy Conditions

Energy Conditions of Built-In Inflation Models