Inflation

The shortcomings of the Standard Big Bang Cosmological Model as well as their resolution in the context of inflationary cosmology are discussed. The inflationary scenario and the subsequent oscillation and decay of the inflaton field are then studied in some detail. The density perturbations produced during inflation and their evolution during the matter dominated era are presented. The temperature fluctuations of the cosmic background radiation are summarized. The non-supersymmetric as well as the supersymmetric hybrid inflationary model is introduced and the `reheating' of the universe is analyzed in the context of the latter and a left-right symmetric gauge group. The scenario of baryogenesis via a primordial leptogenesis is considered in some detail. It is, finally, pointed out that, in the context of a supersymmetric model based on a left-right symmetric gauge group, hybrid inflation, baryogenesis via primordial leptogenesis and neutrino oscillations are linked. This scheme, supplemented by a familiar ansatz for the neutrino Dirac masses and mixing of the two heaviest families and with the MSW resolution of the solar neutrino puzzle, implies that the tau-neutrino mass lies approximately between 1 and 9 eV. The mu-tau mixing angle is predicted to lie in a narrow range which will be partially tested by the Chorus/Nomad experiment.