New scenario for the early evolution of the Universe

We propose that the Universe was created from 'nothing' with a relatively small number of particles and quickly relaxed to a quasiequilibrium state at the Planck parameters. The classic cosmological solution for this Universe with a Λ term has two branches divided by a gap. The quantum process of tunneling between the cosmological solution branches and kinetics of the second order relativistic phase transition in a supersymmetric SU(5) model on GUT scale are investigated using numerical methods. The Einstein equations are solved together with the equations of relaxation kinetics. Another quantum geometrodynamics process (the bounce from a singularity) and the Wheeler-DeWitt equation are also investigated. The computer experiments show that because of the rapid character of the relaxation processes and the absence in the inflaton potential of peculiarities that are able to delay the system in the overcooled phase, the usual type of inflation regime is not realized. For the formation of the observed number of particles a model of a slowly swelling Universe as the result of the multiple reproduction of cosmological cycles arises naturally. copyright 1997 The American Physical Society