有效的精髓理论：w<-1的一面揭开面纱
The Effective Theory of Quintessence: the w<-1 Side Unveiled
摘要：
我们研究一般的单场暗能量模型，通过参数化的最一般的理论，他们的扰动周围一个给定的背景，包括更高的导数条款。在适当的限度内，这种方法再现了标准的精髓，k-本质和幽灵凝聚。我们没有发现与状态方程w_Q < -1或穿越幻肢分界线w_Q =-1相关的一般病理学。稳定性要求暗能量的w_Q < -1侧在宇宙学尺度上表现为具有几乎为零的声速的k-本质流体。这意味着当与w_Q < -1或穿过体模分界线的数据模型进行比较时，应将声速设置为零。我们总结了典型平面（1+w_Q）与声速平方的理论和稳定性约束。
英文摘要：
We study generic single-field dark energy models, by a parametrization of the most general theory of their perturbations around a given background, including higher derivative terms. In appropriate limits this approach reproduces standard quintessence, k-essence and ghost condensation. We find no general pathology associated to an equation of state w_Q < -1 or in crossing the phantom divide w_Q = -1. Stability requires that the w_Q < -1 side of dark energy behaves, on cosmological scales, as a k-essence fluid with a virtually zero speed of sound. This implies that one should set the speed of sound to zero when comparing with data models with w_Q < -1 or crossing the phantom divide. We summarize the theoretical and stability constraints on the quintessential plane (1+w_Q) vs. speed of sound squared.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
