标题： 宇宙学FRW模型中空间曲率的不同表现 显示英文标题

标题： Differing Manifestations of Spatial Curvature in Cosmological FRW Models

摘要： 我们发现了关于（全局）空间曲率参数$K$在测地线方程中与决定背景时空及其扰动时间演化的 Friedmann 方程中相应参数之间不匹配的统计证据。这种不匹配，以下称为“曲率滑移”，在假设 SH0ES 关于当前膨胀率的先验条件时尤为明显。 该结果基于 Planck 卫星 (P18) 的宇宙微波背景 (CMB) 观测数据、暗能量巡天 (DES) 第一年的结果、重子声波振荡 (BAO) 数据以及 Pantheon SNIa (SN) 星表（在较低显著性水平下）的联合分析。 例如，当分别考虑 P18+SH0ES、P18+DES+SH0ES 和 P18+BAO+SH0ES 时，否定零假设的赌盘几率大于$10^7$:1，即 1400:1 和 1000:1。 涉及 SNIa 的数据集大大削弱了这一曲率滑移现象。值得注意的是，即使不施加 SH0ES 先验条件，在考虑 P18+DES 和 P18+BAO 时，否定零假设的赌盘几率仍分别为 70:1 和 160:1。 当施加 SH0ES 先验条件时，允许非零“曲率滑移”的修正模型的整体拟合显著优于 Λ$\Lambda$CDM 模型，这由显著的 Deviance Information Criterion (DIC) 增益所体现，范围从 7 到 23 不等，具体取决于所考虑的数据集组合。 甚至与 K$\Lambda$CDM 模型相比，在排除 SN 数据的情况下，所提出的模型也能导致显著但较小的 DIC 增益。 我们的发现可能被解释为 FRW 度规的理想化最大对称性质与基于广义相对论的同质同向 Λ$\Lambda$CDM 模型的动力学演化之间的固有不一致性。 显示英文摘要

摘要： We find statistical evidence for a mismatch between the (global) spatial curvature parameter $K$ in the geodesic equation for incoming photons, and the corresponding parameter in the Friedmann equation that determines the time evolution of the background spacetime and its perturbations. The mismatch hereafter referred to as `curvature-slip' is especially evident when the SH0ES prior on the current expansion rate is assumed. This result is based on joint analyses of cosmic microwave background (CMB) observations with the PLANCK satellite (P18), first year results of the Dark Energy Survey (DES), Baryonic Oscillation (BAO) data, and - at a lower level of significance - also on Pantheon SNIa (SN) catalog. For example, the betting odds against the Null Hypothesis are greater than $10^7$:1, 1400:1 and 1000:1 when P18+SH0ES, P18+DES+SH0ES, and P18+BAO+SH0ES, respectively, are considered. Datasets involving SNIa weaken this curvature slip considerably. Notably, even when the SH0ES prior is not imposed the betting odds for the rejection of the Null Hypothesis are 70:1 and 160:1 in cases where P18+DES and P18+BAO are considered. When the SH0ES prior is imposed, global fit of the modified model (that allows for a nonvanishing `curvature slip') strongly outperforms that of $\Lambda$CDM as is manifested by significant Deviance Information Criterion (DIC) gains, ranging between 7 and 23, depending on the dataset combination considered. Even in comparison to K$\Lambda$CDM the proposed model results in significant, albeit smaller, DIC gains when SN data are excluded. Our finding could possibly be interpreted as an inherent inconsistency between the (idealized) maximally symmetric nature of the FRW metric, and the dynamical evolution of the GR-based homogeneous and isotropic $\Lambda$CDM model (abridged)