[论文解读] Constraints on interacting dark energy revisited: implications for the Hubble tension

Gabriel A. Hoerning, Ricardo G. Landim+4 more|arXiv (Cornell University)|Aug 10, 2023

Cosmology and Gravitation Theories被引用 11

一句话总结

论文重新评估带有包括哈勃率涨落的修正扰动方程的表观互作暗能模型，利用 Planck 2018、Pantheon+ SNIa、BAO、RSD 数据以及 SH0ES 进行对比，未发现对 ΛCDM 的显著偏好；某些模型在一定程度缓解哈勃张力，但在全部数据联合时仍不兼容。

ABSTRACT

We revisit a class of coupled dark energy models where dark energy interacts with dark matter via phenomenological energy exchange terms. We include the perturbation of the Hubble rate in the interaction term, which was absent in previous works. We also consider more recent data sets such as cosmic microwave background (CMB) anisotropies from ext{Planck} 2018, type I-a supernovae (SNIa) measurements from Pantheon+ and data from baryon acoustic oscillations (BAO), and redshift space distortions (RSD). One of the models presents a strong incompatibility when different cosmological datasets are used. We analyze the influence of the SH0ES Cepheid host distances on the results and, although for one model the discrepancy of $H_0$ is reduced to $3.2σ$ when compared to the value obtained by the extit{Planck} collaboration and $3.6σ$ when compared to the SH0ES team, joint analysis is incompatible. Including BAO with RSD shows incompatibility with SH0ES for all models considered here. We perform a model comparison and although there is a preference for interacting dark energy over $Λ$CDM for all the models for joint analysis CMB+BAO+RSD+SNIa, most of the 2D contours do not overlap. We conclude that the models of interactions in the dark sector considered in this paper are not flexible enough to fit all the cosmological data including values of $H_0$ from SH0ES in a statistically acceptable way. Therefore, the addition of one extra degree of freedom (i.e. the coupling between dark matter and dark matter) does not help enough to alleviate the already existing tension in the vanilla $Λ$CDM, suggesting that the models would need to be modified to include further flexibility of predictions to help elucidate this issue.

研究动机与目标

• 激发对暗 sector 相互作用作为解决 ΛCDM 张力，特别是 H0 张力的探索。
• 通过在 IDE 模型中加入 Hubble 率的扰动来包含与规范一致的扰动修正。
• 用更新的数据集（Planck 2018、Pantheon+、BAO、RSD）约束三个 IDE 模型，并评估其与 SH0ES H0 的兼容性。
• 使用贝叶斯证据和 χ² 指标对比ΛCDM 的模型。

提出的方法

• 采用一类 IDE 模型，Q = H(λ1 ρdm + λ2 ρde)，并研究背景与扰动进化。
• 通过包含规范不变量所需的 δH 项来修正扰动方程。
• 使用修改后的 CLASS 和 PLINY 进行带嵌套采样的 MCMC 分析，以获得参数后验和贝叶斯证据。
• 利用 Planck 2018 CMB、Pantheon+ SNIa、BAO、RSD 数据，部分分析包括 SH0ES H0 锚定。

Figure 1: 2-D contours (68% and 95% C.L.) of selected cosmological parameters for Model I, using different combinations of datasets. The inclusion of datasets other than CMB improves significantly the constraints. The different contours, however, do not superimpose and the degeneracy between $\Omega

实验结果

研究问题

• RQ1 具有 Q ∝ H(ρdm, ρde) 的 IDE 模型能否像 ΛCDM 一样拟合综合宇宙学数据？
• RQ2 包括哈勃率扰动是否会影响对 IDE 耦合的约束以及推断的 H0？
• RQ3 当把所有数据集（CMB、BAO、RSD、SNIa）结合时，IDE 模型是否能缓解 H0 张力？
• RQ4 在最新数据下，是否对 IDE 相对 ΛCDM 有统计学上的偏好？
• RQ5 在与低红移探针对比的基准下，IDE 模型与 SH0ES 的 H0 测量有多大兼容性？

主要发现

• 一个 IDE 模型（Model III）在部分缓解 H0 张力方面最优，但在全部数据联合时仍存在不兼容。
• 在扰动方程中包含 δH 会收紧对耦合常数的约束并改变参数之间的简并性。
• CMB+BAO+SNIa+RSD 联合分析显示任一 IDE 模型在所有数据集的二维等高线没有重叠，意味着与 SH0ES H0 仍存在张力。
• 贝叶斯证据并未强烈支持 IDE 相对于 ΛCDM（对于所有模型，使用 CMB+BAO+SNIa+RSD 时 |Δχ²| < 1）。
• 对于 Model III，在联合数据下，H0 上移至 68.11^{+0.21}_{-0.22} km/s/Mpc，降低但未消除与 SH0ES 的张力（4.6σ 相比 SH0ES）。
• SH0ES 锚定降低了所有模型的低红移与高红移数据集之间的重叠，表明在耦合暗能框架下张力仍然存在。

Figure 2: 2-D contours (68% and 95% C.L.) of selected cosmological parameters for Model II, using different combinations of datasets. Contrary to Model I, the degeneracies between some cosmological parameters are broken by the combination of datasets. The contours of all datasets (but SH0ES) are ove