论文标题
与CMB各向异性的早期暗能量的相过渡的限制
Constraints on the phase transition of Early Dark Energy with the CMB anisotropies
论文作者
论文摘要
在最近的哈勃张力问题的背景下，早期的暗能量（EDE）模型引起了人们的关注。在这里，我们通过考虑EDE产生的新密度波动来扩展这些模型，该密度波动在重组阶段衰减。我们解决了在EDE作为等效性扰动时产生的暗能流体中密度扰动的演变。假设等效模式以幂律功率谱为特征，并且与标准绝热模式不相关，我们计算了CMB角幂谱。通过使用Markov-Chain Monte Carlo方法将它们与Planck数据进行比较，我们获得了EDE参数的零一致值，$ H_0 = 67.56^{+0.65} _ { - 0.66}〜\ \ \ \ \ \ \ \ \ \ Mathrm {Km} \ Mathrm {mpc}^{ - 1} $ at $ 68 \％$ cl。此$ H_0 $值几乎与$λ$ CDM型号中的普朗克值几乎相同IA型超新星观测。包括CMB镜头，BAO，Supernovae和SH0ES数据集，我们发现$ H_0 = 68.94^{+0.47} _ { - 0.57}〜\ Mathrm {km} \，\，\ Mathrm {s}} EDE的相转换引起的波动的幅度限制为$ 1 $ - $ 2 $ 2 $ 2 $ 2 $的$ 2 $占绝热模式的幅度。这是如此之小，以至于在CMB角光谱中不能出现这种非标准波动。总之，由我们最简单的EDE相变模型引起的异位效应波动并不能很好地解释哈勃张力。
Early dark energy (EDE) models have attracted attention in the context of the recent problem of the Hubble tension. Here we extend these models by taking into account the new density fluctuations generated by the EDE which decays around the recombination phase. We solve the evolution of the density perturbations in dark energy fluid generated at the phase transition of EDE as isocurvature perturbations. Assuming that the isocurvature mode is characterized by a power-law power spectrum and is uncorrelated with the standard adiabatic mode, we calculate the CMB angular power spectra. By comparing them to the Planck data using the Markov-Chain Monte Carlo method, we obtained zero-consistent values of the EDE parameters and $H_0=67.56^{+0.65}_{-0.66}~\mathrm{km} \, \mathrm{s}^{-1} \mathrm{Mpc}^{-1}$ at $68 \%$ CL. This $H_0$ value is almost the same as the Planck value in the $Λ$CDM model, $H_0=67.36 \pm 0.54~\mathrm{km} \, \mathrm{s}^{-1} \mathrm{Mpc}^{-1}$, and there is still a $\sim 3.5 σ$ tension between the CMB and Type Ia supernovae observations. Including CMB lensing, BAO, supernovae and SH0ES data sets, we find $H_0=68.94^{+0.47}_{-0.57}~\mathrm{km} \, \mathrm{s}^{-1} \mathrm{Mpc}^{-1}$ at $68 \%$ CL. The amplitude of the fluctuations induced by the phase transition of the EDE is constrained to be less than $1$--$2$ percent of the amplitude of the adiabatic mode. This is so small that such non-standard fluctuations cannot appear in the CMB angular spectra. In conclusion, the isocurvature fluctuations induced by our simplest EDE phase transition model do not explain the Hubble tension well.
