f(R)-Cosmolgy from Early Universe Upto Future Cosmic Collapse and its Avoidance
Abstract
In the present model, a unified picture of cosmology from early inflation to late acceleration is obtained from f(R)- gravity with non-linear terms R2 and R5 of scalar curvature R. It is discussed that elementary particles and radiation are produced during early inflation. The emitted radiation thermalizes the universe to a very high temperature 1018 GeV. The exit of the universe from inflationary phase is followed by deceleration due to radiation-dominance heralding the standard cosmology with background radiation having the initial temperature 1018 GeV. It is found that dark matter is induced by curvature and baryonic matter is produced during inflation. Radiation-dominated phase is followed by deceleration due to matter-dominance. The curvature-induced phantom dark energy dominates at the red-shift z = 0.303 causing the late acceleration. It is found that the universe will collapse in future. Further, it is investigated that back-reaction of quantum particles produced near the collapse time can avoid cosmic collapse and the universe will escape to revival of the state of early universe.