论文标题
对宇宙紧张局势的实证研究
An empirical investigation into cosmological tensions
论文作者
论文摘要
$ h_0 $张力的可能性是$λ$ CDM模型以外的物理学的标志，是现代宇宙学中最令人兴奋的可能性之一。解决此问题的挑战使几个因素变得复杂，包括$σ_8$参数的紧张局势加剧，当$σ_8$ h_0 $上提出时。此外，不应低估问题的观点，因为$ h_0 $的紧张张力也可以解释为在声学范围的大小上的张力，$ r_s $，值得进行适当的讨论。文献中的常见方法是提出一个可以解决张力并将理论的新参数视为自由的新模型。但是，允许其他参数变化通常会导致对推断的宇宙学参数的不确定性更大，从而导致由于后部的宽广而导致张力明显放松，而不是$ h_ {0} $的中心值的真正变化。为了避免这种情况，我们在这里考虑采用一种经验方法，该方法假定$λ$ CDM扩展的特定非标准值，我们分析了在张力的上下文中的重要参数如何变化。出于我们的目的，我们研究了标准宇宙学模型的简单扩展，例如幻影de组件（具有状态$ W <-1 $）和早期宇宙中额外的相对论物种（因此$ n_ {eff}> 3.046 $）。我们获得了$ W $和$ n_ {eff} $的变化与$ h_0 $，$ r_s $和$σ_8$的变化之间的关系。通过这种方式，提供了$ H_0 $和$σ_8$之间的经验关系，这是理解哪些类别的理论模型以及哪些特征可以打破两个紧张局势之间的相关性的第一步。
The possibility that the $H_0$ tension is a sign of a physics beyond the $Λ$CDM model is one of the most exciting possibilities in modern cosmology. The challenge of solving this problem is complicated by several factors, including the worsening of the tension on $σ_8$ parameter when that on $H_0$ is raised. Furthermore, the perspective from which the problem is viewed should not be underestimated, since the tension on $H_0$ can also be interpreted as a tension on the size of the acoustic horizon, $r_s$, which deserves proper discussion. The common approach in the literature consists in proposing a new model that can resolve the tension and treat the new parameters of the theory as free in the analysis. However, allowing additional parameters to vary often results in larger uncertainties on the inferred cosmological parameters, causing an apparent relaxing in the tension due to the broaden in the posterior, instead of a genuine shift in the central value of $H_{0}$. To avoid this, we consider here an empirical approach that assumes specific non-standard values of the $Λ$CDM extensions and we analyze how the important parameters in the context of the tension vary accordingly. For our purposes, we study simple extensions of the standard cosmological model, such as a phantom DE component (with Equation of State $w < -1$) and extra relativistic species in the early Universe (so that $N_{eff} > 3.046$). We obtain relations between variation in the value of $w$ and $N_{eff}$ and changes in $H_0$, $r_s$ and $σ_8$. In this way an empirical relation between $H_0$ and $σ_8$ is provided, that is a first step in understanding which classes of theoretical models, and with which characteristics, could be able to break the correlation between the two tensions.
