论文标题
延迟扩展可以解决$ H_0 $和$σ_8$张力吗？
Can late-time extensions solve the $H_0$ and $σ_8$ tensions?
论文作者
论文摘要
我们分析了$λ$ CDM扩展历史记录必须具有的任何延迟时间修改，以便始终如一地解决$ H_0 $和$σ_8$张力。采用独立于模型的方法，我们获得了一组必要条件，这些条件可应用于通用的延迟扩展。我们的结果是完全分析的，仅基于以下假设：$λ$ CDM背景的偏差仍然很小。对于具有状态$ W（z）$的深色能液的具体情况，我们得出以下一般要求：（i）在某些$ z $（ii）解决$ h_0 $张力要求$ w（z）<-1 $ y y y $ z $（ii）解决$ h_0 $ $ h_0 $和$σ_8$ w（z）$ w（z）$ W（z）$ w（z）$ crocking phantom divide。最后，我们还允许对有效重力常数的小偏差。在这种情况下，我们的方法仍然能够约束这些偏差的功能形式。
We analyze the properties that any late-time modification of the $Λ$CDM expansion history must have in order to consistently solve both the $H_0$ and the $σ_8$ tensions. Taking a model-independent approach, we obtain a set of necessary conditions that can be applied to generic late-time extensions. Our results are fully analytical and merely based on the assumptions that the deviations from the $Λ$CDM background remain small. For the concrete case of a dark energy fluid with equation of state $w(z)$, we derive the following general requirements: (i) Solving the $H_0$ tension demands $w(z)<-1$ at some $z$ (ii) Solving both the $H_0$ and $σ_8$ tensions requires $w(z)$ to cross the phantom divide. Finally, we also allow for small deviations on the effective gravitational constant. In this case, our method is still able to constrain the functional form of these deviations.
