论文标题
为什么零空间曲率特别？
Why is zero spatial curvature special?
论文作者
论文摘要
几种观察探针提供了几乎空间平坦的证据，包括宇宙微波背景（CMB）和BARYON声学振荡（BAO）的证据。但是，除了通货膨胀外，在这种情况下，仅在无限时间的限制下，空间平坦的宇宙没有强大的先验动机。使用弯曲时空中的重新归一化组（RG）技术，我们在这项工作中提出了空间平坦度的理论动机。从一般的时空开始，RG的第一步，粗粒，使Friedmann-Lema-Robertson-Walker（FLRW）指标具有一组参数。然后，我们研究了曲率参数的重新缩放特性，并发现FLRW度量的零空间曲率被选为宇宙学扰动的独特无标度，非标准背景。
Evidence for almost spatial flatness of the Universe has been provided from several observational probes, including the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO) from galaxy clustering data. However, other than inflation, and in this case only in the limit of infinite time, there is no strong a priori motivation for a spatially flat Universe. Using the renormalization group (RG) technique in curved spacetime, we present in this work a theoretical motivation for spatial flatness. Starting from a general spacetime, the first step of the RG, coarse-graining, gives a Friedmann-Lemaître-Robertson-Walker (FLRW) metric with a set of parameters. Then, we study the rescaling properties of the curvature parameter, and find that zero spatial curvature of the FLRW metric is singled out as the unique scale-free, non-singular background for cosmological perturbations.
