Evolution of Inflationary Universe in Extended Gravitational Theories

点击翻译按钮获取中文摘要

Inflationary Universe model, which was proposed by A. Guth and present researcher independently, is a standard scenario of early universe. This is recognized not only as a consequence of unified theories of elementary interaction, but as an essential step of the creation of universe. This model is also supported by observations. Recently COBE (Cosmic background explorer) discovered the fluctuation of background radiation, and found that the spectrum of the fluctuations is very consistent with the prediction of Inflationary model.In spite of the success of this model, there is a severe problem whether any inhomogeneous and anisotropic universe can evolve to homogeneous and isotropic universe or not. In this research, we investigated this problem called "Cosmic No-hair Conjecture" by using new formalism of the calculation of general relativity, Regge Calculus. For the homogeneous and anisotropic universe, we found the constraint for the initial condition which evolve to inflationary universe not only for usual exponential expanding universe model, but also for the power law expanding models. However, there still remains problem that Hamiltonian constraint is inconsistent with evolution equations for inhomogeneous models.We also investigated formation of topological defects in early universe during phase transition, and showed that "texture" give a consistent density fluctuation for structure formation in the Big Bang Model,in particular, the deviation from Gaussian helps the formation of large scale structure.