Relativistic Astrophysics Based on Brane Cosmologyブレイン宇宙モデルに基づく相対論的宇宙物理学

弦理论中出现的“膜”概念，彻底改变了早期宇宙和强引力现象的看法。它还改变了卡鲁扎和克莱因传统的旧观点对更高维度的看法，即膜的存在使更大的额外维度成为可能和可见。此外，兰德尔和桑德鲁姆提出的新的膜模型给出了新的致密化机制。特别是第二种模型，由于它在高维世界中给出了牛顿引力而不需要紧致，因此成为宇宙学家关注的焦点。这个模型提供了与传统的Kaluza-Klein紧凑化完全不同的方面。因此，许多相对主义者和宇宙学家都在研究它，以寻找新的世界观。在这种情况下，基于薄膜引力理论分析宇宙学模型和强引力现象，如黑洞或引力崩塌是非常重要的。在这个研究项目中，我们在两位著名的年轻教授(David Wands和David Langlois)的帮助下研究了膜世界的新观点。为了阐明膜引力的性质，我们研究了发热式宇宙模型中的膜碰撞和导致宇宙大爆炸的再热机制。我们还分析了弦理论量子修正中的一些高曲率项的有效理论，讨论了它们的宇宙模型，并提出了新的暴涨假说。

The idea of "brane", which appeared in string theory, changes completely the view of the early universe and strong gravitational phenomena. It also changes the view of higher dimensions from the conventional old idea by Kaluza and Klein, i.e., the existence of a brane makes a large extra dimension possible and visible. Furthermore new brane models proposed by Randall and Sundrum give new types of compactification mechanism. Especially, the second model has become the focus of cosmologist's attention because it gives the Newtonian gravity in higher dimensional world without compactification. This model provides definitely a different aspect from the conventional Kaluza-Klein compactification. Hence many relativists and cosmologists are studying it to look for new world view. Under such a circumstance, it is very important to analyze cosmological models and strong gravitational phenomena such as a black hole or gravitational collapse based on this brane gravitational theory. In this research project, we study new view of the brane world with the help of two prominent young professors (David Wands and David Langlois).In order to clarify the properties of brane gravity, we have studied brane collision in the ekpyrotic cosmological model, which could be an alternative of the standard inflation scenario, and the reheating mechanism, which leads the universe to a big bang. We have also analyzed some effective theories with higher curvature terms, which come from quantum correction of string theory discussed their cosmological models, and proposed new inflationary scenario.