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arXiv 2008.10237astro-ph.COgr-qc
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在暗区有负的宇宙学常数？

Negative cosmological constant in the dark sector?

Rodrigo Calderón, Radouane Gannouji, Benjamin L'Huillier, David Polarski

备注：
12 pages, 5 figures, 4 tables. v3: Matches published version
发表信息：
Phys. Rev. D 103, 023526 (2021)
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摘要：

我们考虑的可能性，我们的宇宙的黑暗部门包含一个负的宇宙学常数称为$λ$。为了使此类模型可行，暗区应该包含一个负责后期加速膨胀率（$X$）的额外组件。我们探讨了这些模型的膨胀历史的一致性$Λ$冷暗物质模型的出发点。对于一个大类我们的模型的加速膨胀是瞬态的模型参数的非平凡的依赖。所有模型与$w_X>-1$最终将合同，我们推导出的比例因子$a(t)$在其最大值附近的解析表达式。我们还发现，在一个大撕裂结束的制度，尘埃状物质密度相比，$λ$的模型的比例因子可以忽略不计。我们进一步解决这些模型的可行性，特别是当一个高的$H_0$考虑。虽然我们没有发现一个非零$λ$的决定性证据，最好的模型得到了一个幻影行为的红移$z\gtrsim 1$与非零$λ$更高的证据。$h$的观察值显著高于$0.70$将是其活力的决定性测试。

英文摘要：

We consider the possibility that the dark sector of our Universe contains a negative cosmological constant dubbed $λ$. For such models to be viable, the dark sector should contain an additional component responsible for the late-time accelerated expansion rate ($X$). We explore the departure of the expansion history of these models from the concordance $Λ$ Cold Dark Matter model. For a large class of our models the accelerated expansion is transient with a nontrivial dependence on the model parameters. All models with $w_X>-1$ will eventually contract and we derive an analytical expression for the scale factor $a(t)$ in the neighborhood of its maximal value. We find also the scale factor for models ending in a Big Rip in the regime where dustlike matter density is negligible compared to $λ$. We address further the viability of such models, in particular when a high $H_0$ is taken into account. While we find no decisive evidence for a nonzero $λ$, the best models are obtained with a phantom behavior on redshifts $z\gtrsim 1$ with a higher evidence for nonzero $λ$. An observed value for $h$ substantially higher than $0.70$ would be a decisive test of their viability.

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