暴胀宇宙学的前大爆炸几何扩展
Pre-big bang geometric extensions of inflationary cosmologies
摘要：
罗伯逊-沃克时空在一个大类中被几何地扩展到更大的宇宙学，包括具有零和负宇宙学时间的时空点。在扩展的宇宙学中，大爆炸是类光的，虽然是奇异的，但它继承了原始时空的某些几何结构。类空测地线在宇宙学时间零点子流形上是连续的，而时间零点子流形的参数是费米空间切片的半径，即从一个同向运动的观测者到大爆炸沿类空测地线的适当距离。度规的连续延拓和观测者费米度规系数$g_{ττ}$的连续可微延拓限制了具有大爆炸前宇宙学时间坐标的时空点的几何。在我们的推广中，大爆炸在某种意义上是二维的，这与量子引力的某些发现是一致的。
英文摘要：
Robertson-Walker spacetimes within a large class are geometrically extended to larger cosmologies that include spacetime points with zero and negative cosmological times. In the extended cosmologies, the big bang is lightlike, and though singular, it inherits some geometric structure from the original spacetime. Spacelike geodesics are continuous across the cosmological time zero submanifold which is parameterized by the radius of Fermi space slices, i.e, by the proper distances along spacelike geodesics from a comoving observer to the big bang. The continuous extension of the metric, and the continuously differentiable extension of the leading Fermi metric coefficient $g_{ττ}$ of the observer, restrict the geometry of spacetime points with pre-big bang cosmological time coordinates. In our extensions the big bang is two dimensional in a certain sense, consistent with some findings in quantum gravity.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
