论文标题
关于$λ$ CDM的独特性，类似于均质和各向同性宇宙学中的唯一性
On the uniqueness of $Λ$CDM-like evolution for homogeneous and isotropic cosmology in General Relativity
论文作者
论文摘要
我们解决了在空间平面$λ$ CDM的唯一性的问题，类似于FLRW宇宙学中的类似于一般相对论的Evolution，即，除空间平坦的$λ$ CDM以外的任何模型是否可以引起相同类型的比例因子进化。首先，我们使用State-Finder Diagnostic的课程，使用$λ$ CDM模型详细说明了$λ$ cdm样的进化或运动学/宇宙学变性。然后，我们考虑了两个在黑暗扇区中相互作用的模型：耦合流体流体模型和耦合的典型模型。我们通过cosmographic条件$ j = 1 $（$ j $是混蛋参数），使用空间flat $λ$ CDM模型来实施\ emph {kinematic}变性，从而依次确定了交互项的功能，该功能是先验未指定的。我们认为，总的来说，这种掌握条件仅与空间平坦相一致。 Employing a dynamical system approach, we show that the spatially flat coupled fluid-fluid interacting models kinematically degenerate with $Λ$CDM must necessarily be based on a phantom fluid, whereas the set of physically viable spatially flat coupled quintessence models with power law or exponential potential kinematically degenerate to $Λ$CDM is of measure zero.我们的分析确定，具有非光流体流体或具有功率定律和指数势的耦合典型模型的耦合流体流体模型永远无法再现类似于$λ$ CDM的宇宙学演化。根据观察性的宇宙学紧张局势，对我们发现的天体物理后果进行了定性讨论。
We address the question of the uniqueness of spatially flat $Λ$CDM-like evolution for FLRW cosmologies in General Relativity, i.e. whether any model other than the spatially flat $Λ$CDM can give rise to the same type of scale factor evolution. Firstly, we elaborate on what we exactly imply by a $Λ$CDM-like evolution or kinematic/cosmographic degeneracy with the $Λ$CDM model, using the lessons from the statefinder diagnostic. Then, we consider two models with interaction in the dark sector: coupled fluid-fluid model and coupled quintessence model. We enforce the \emph{kinematic} degeneracy with the spatially flat $Λ$CDM model via the cosmographic condition $j=1$ ($j$ being the jerk parameter), which in turn fixes the function of the interaction term that is a priori unspecified. We argue that in General Relativity this cosmographic condition is consistent only with spatial flatness. Employing a dynamical system approach, we show that the spatially flat coupled fluid-fluid interacting models kinematically degenerate with $Λ$CDM must necessarily be based on a phantom fluid, whereas the set of physically viable spatially flat coupled quintessence models with power law or exponential potential kinematically degenerate to $Λ$CDM is of measure zero. Our analysis establishes that coupled fluid-fluid models with non-phantom fluids or coupled quintessence models with power law and exponential potential can never reproduce a cosmological evolution similar to that of the $Λ$CDM. The astrophysical consequences of our findings are qualitatively discussed in light of observational cosmological tensions.
