论文标题
黑暗部门的负宇宙常数？
Negative cosmological constant in the dark sector?
论文作者
论文摘要
我们认为，我们宇宙的黑暗扇区包含一个负宇宙的$λ$的可能性。对于这样的模型，黑暗扇区应包含负责延迟加速率（$ x $）的额外组件。我们探索了这些模型的扩展历史的偏离，从一致性$λ$冷暗物质模型中。对于我们的大量模型，加速扩展是瞬态的，对模型参数具有非平凡的依赖性。所有具有$ W_X> -1 $的型号最终都将收缩，我们在其最大值附近得出了比例因子$ a（t）$的分析表达式。我们还发现模型的比例因素在尘土飞扬的物质密度与$λ$相比可以忽略不计。我们进一步解决了此类模型的生存能力，特别是当考虑到高$ H_0 $时。尽管我们没有发现非零$λ$的决定性证据，但最佳型号是在红移$ z \ gtrsim 1 $上具有幻影行为的最佳模型，而非零$λ$的证据更高。 $ h $的观察值高于$ 0.70 $，将是对其生存能力的决定性测试。
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.
