f(R)-COSMOLGY FROM EARLY UNIVERSE UPTO FUTURE COSMIC COLLAPSE AND ITS AVOIDANCE

In the present model, a unified picture of cosmology from early inflation to late acceleration is obtained from f(R)− gravity with nonlinear terms R and R 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 ∼ 10GeV. 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 ∼ 10GeV. It is found that dark matter is induced by curvature and baryonic matter is produced during inflation. Radiationdominated 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 1