论文标题
FRW宇宙学中的岛屿
Islands in FRW Cosmologies
论文作者
论文摘要
我们在FRW宇宙学中搜索候选岛屿区域，这些区域由辐射，宇宙常数$λ$和非零空间曲率支持。假定辐射处于热状态。我们应用[ARXIV：2008.01022]中引入的必要条件。对于带有$λ<0 $的开放式宇宙和封闭的宇宙，Friedmann方程都以时间对称性切片的形式接受了回忆解决方案。就封闭的宇宙而言，总有一个岛屿是整个库奇片。但是，对于$λ<0 $，我们还在时空的中间，一个有限大小的候选岛地区。就开放宇宙而言，我们只以$λ<0 $的价格找到一个候选岛地区，该地区出现在周转时间。它从径向坐标的有限值开始，并延伸至无穷大。从开放式宇宙和封闭的宇宙中，我们得出结论，允许岛屿存在的关键要素是负宇宙常数。我们在时间对称切片中提供分析结果，并在整个时空中使用数字支持我们的结果。
We search for candidate island regions in FRW cosmologies supported by radiation, cosmological constant $Λ$, and non-zero spatial curvature. The radiation is assumed to be in a thermal state. We apply the necessary conditions introduced in [arXiv:2008.01022]. Both for the open and closed universes with $Λ<0$, the Friedmann equation admits recollapsing solutions with a time-symmetric slice. In the case of closed universes, there is always an island that is the whole Cauchy slice. However, for $Λ<0$, we also find another finite-sized candidate island region, in the middle of the spacetime, at the turnaround time. In the case of the open universes, we only find a candidate island region for $Λ<0$, that appears at the turnaround time. It starts from a finite value of the radial coordinate and extends to infinity. Looking at both open and closed universes, we conclude that the key ingredient that allows the existence of islands is the negative cosmological constant. We provide analytic results along the time-symmetric slices and support our results with numerics in the whole spacetime.
