Abstract Details

Name: Louise Rebecca
Affiliation: Christ University
Conference ID: ASI2020_222
Title : Planckian Pre Big Bang Phase of the universe
Authors and Co-Authors : Louise Rebecca (Author) C. Sivaram (Co-Author) Kenath Arun (Co-Author)
Abstract Type : Oral
Abstract Category : General Relativity and Cosmology
Abstract : One major problem with the big bang model is the presence of a singularity when density and curvature become infinite. Here we discuss a possible non-singular beginning of the universe. According to the standard evolving cosmological model, the scale factor R of the universe is related to the corresponding background temperature T as, RT=constant. For the present epoch this implies that RT~3x10^28 cmK which remains a constant during the expansion. Quantum considerations imply that the earliest epoch of the universe would have been the Planck epoch starting at 10^-44s with Planck temperature. At this epoch we get a scale factor for the universe given as, (R_min)(T_pl)~3x10^28 cmK, which gives a minimal scale factor of (R_min)=10^-3cm. This would imply that when extrapolating the observed expansion of the Universe back in time to the Planck epoch with a maximal temperature of 10^32K leads not to a singularity but a finite size of 10^-3cm. In this model we suggest that the universe initially began with a fluctuation having Planck energy and a scale factor of 10^-33cm which then expanded at constant Planck density, to a size of 10^-3cm. This expansion (an increase in size by an order of 10^30) at constant density will create particle numbers of the order of 10^90 with each having Planck energy. These energies were red-shifted by an order of 10^30. We also suggest a model of a time-varying cosmological constant that could account for this decrease in energy during the expansion of the universe. In this work we have a smooth construction starting from the Planck scale onto the usual big bang era after which the vacuum energy drops rapidly and the expansion leads to the radiation dominated era.