标题： 演化的暗物质领域和暗维度情景 显示英文标题

标题： Evolving Dark Sector and the Dark Dimension Scenario

摘要： 弦理论自然地导致暗能量不稳定，可能如Swampland de Sitter猜想所描述的那样在演化。 此外，受距离猜想的启发，提出了暗区的统一，其中暗能量的微小导致一个微米大小的额外维度，暗物质是这个额外维度中的KK引力子激发态。 我们考虑一种自然的可能性，即暗维度的半径随着暗能量的减少而变化，从而导致暗物质质量的变化。 这将暗能量的减少与暗物质质量的变化相关联，因为它们都依赖于控制额外维度半径的标量场$\phi$的变化。 对于$\phi$的小范围，这一想法的一个简单实现是选择一个局部形式为$V=V_0\ {\rm exp}(-c\phi)$的势能和暗物质质量$m_{\rm DM}=m_0\ {\rm exp}(-c' \phi)$，其中$\phi$的符号被选择为$c'\geq 0$，而$c$的符号有两种选择，取决于当暗能量占主导时暗维度是膨胀还是收缩。 我们发现与DESI的DR2实验数据结合超新星测量结果有很好的一致性，并且重现了CPL参数化相同的显著性，同时提供了对DESI和DESP基于物理模型报告的明显类phantom行为（$w<-1$）的自然解释。 无论使用哪种超新星数据集，都倾向于$c'$和$c$取非零值，这些值在普朗克单位下处于由Swampland准则建议的预期$O(1)$范围内。 特别是，对于所有数据集组合（包括超新星数据），与$c'\simeq 0.05 \pm 0.01$有显著的一致性，并接近暗物质领域缺乏第五力检测所要求的实验上限$c'\lesssim 0.2$。 显示英文摘要

摘要： String theory naturally leads to the expectation that dark energy is not stable, and may be evolving as captured by the Swampland de Sitter conjectures. Moreover, motivated by the distance conjecture a unification of dark sector has been proposed, where the smallness of dark energy leads to one extra dimension of micron size with dark matter being the KK graviton excitations in this extra dimension. We consider the natural possibility that the radius of the dark dimension varies as the dark energy decreases, leading to the variation of the dark matter mass. This correlates the decrease of the dark energy with the variation of the dark matter mass as they depend on the variations of a scalar field $\phi$ controlling the radius of the extra dimension. A simple realization of this idea for small range of $\phi$ is captured by choosing a potential which is locally of the form $V=V_0\ {\rm exp}(-c\phi)$ and dark matter mass $m_{\rm DM}=m_0\ {\rm exp}(-c' \phi)$ where the sign of $\phi$ is chosen such that $c'\geq 0$ while we have two choices for the sign of $c$ depending on whether the dark dimension expands or shrinks when the dark energy dominates. We find excellent agreement with recent experimental data from DESI DR2 combined with SN measurements and reproduces the same significance as CPL parametrization with the added benefit of providing a natural explanation for the apparent phantom behavior ($w<-1$) reported by DESI and DES based on a physical model. Regardless of the SN dataset, there is a preference for non-zero values of $c'$ and $c$ that are in the expected $O(1)$ range in Planck units as suggested by the Swampland criteria. In particular, there is a remarkable consistency with $c'\simeq 0.05 \pm 0.01$ for all dataset combinations including SN, and close to the experimental upper bound of $c'\lesssim 0.2$ demanded by the lack of detection of fifth force in the dark sector.