| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
Inflationary universe model proposed Guth, and Sato independently, almost became a standard model of the very early universe. The important consequence of the inflationary universe model is that the flatness and horizon problems which were essential difficulties in the "Standard Big Bang Model" are solved. However, if we go back to Plankian time, or stand on the quantum cosmology, the universe is very inhomogeneous. It has not yet become clear that such inhomogeneous universe can evolve to homogeneous present one. In the present work, we investigated this proglem by using analytic and numerical method, and obtained the following results.
1. Taking a simplified model that the spherical symmetric region with high vacuum energy density is surrounded by region with low density vacuum density, we investigated the fate of this structure, and found that (1) if the radius is smaller than the horizon of the universe, the region evolves to a black hole, (2) if the region is larger than this ,but smaller than a critical radius, the region evolve to worm hole and (3), in the other case the region simply evolve to de Sitter like universe.
2. By using ADM formalism, we investigated numerically the evolution of spherical symmetric perturbation. We calculated simultaneously Einstein Eq. and Equation of motion of scalar field. We found that if the amplitude of the perturbation is same, apparent horizon is formed earlier stage in the the shorter wave length model. We also found that the space-time structure become very complicate in the realistic models, i.e., many cosmological horizon and apparent horizon are formed.
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