Vv. Burdyuzha et al., A scenario for the initial evolution of a Universe providing the observed number of particles, ASTRON REP, 42(6), 1998, pp. 711-721
It is proposed that the Universe was born from "nothing" with a relatively
small number of particles and relaxed very quickly into a quasi-equilibrium
state with the Planck parameters. The classical cosmological solution for
such a Universe with a cosmological constant Lambda and a number of particl
es less than the critical number has two branches separated by a gap (quasi
-Friedmann and quasi-de Sitter). The quantum process of tunneling between t
hese branches and the kinetics of relativistic phase transitions in a SU(5)
supersymmetry model at energies of similar to 10(16) GeV are investigated
using numerical methods. The Einstein equations are solved together with th
e equations of relaxation kinetics. Another quantum-geometrical process (a
"bounce" from a singularity) and the Wheeler-de Witt equation are also cons
idered. A model of a slowly expanding Universe that can generate the observ
ed number of particles arises in a natural way as a result of multiple repe
titions of cosmological cycles. Results of the first computer experiments t
o study in detail the problem of particle formation in the early Universe a
re presented. These experiments showed that, due to the rapidity of the rel
axation processes and the lack in the inflanton potential of singularties c
apable of keeping the system in a supercooled phase, the usually envisioned
inflatory regime does not arise.