Stable large-scale perturbations in interacting dark-energy model
Stable large-scale perturbations in interacting dark-energy model
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DOI：
10.1088/1475-7516/2013/08/018
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发表时间：
2013
影响因子：
6.4
通讯作者：
Cheng-yi Sun;Rui-Hong Yue
中科院分区：
文献类型：
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作者：
Cheng-yi Sun;Rui-Hong Yue
发现在暗扇形相互作用Q与冷暗物质能量密度（CDM）成正比、暗能量状态方程参数（DE）为常数的模型中，超哈勃尺度上的密度扰动演化是不稳定的。为了避免不稳定性，本文提出了一种新的能量-动量传递的协变模型。然后，我们证明了在一个仅由DE和CDM填充的宇宙中，曲率扰动的大尺度不稳定性是可以避免的。此外，通过引入辐射和重子的附加分量，我们计算了辐射时代的主要非绝热模，发现这些模在单位数量级上以指数的幂律增长。
It is found that the evolutions of density perturbations on the super-Hubble scales are unstable in the models with dark-sector interaction Q proportional to the energy density of cold dark matter (CDM) and constant equation of state parameter of dark energy (DE). In this paper, to avoid the instabilities, we suggest a new covariant model for the energy-momentum transfer between DE and CDM. Then we show that the the large-scale instabilities of curvature perturbations can be avoided in a universe filled only by DE and CDM. Furthermore, by including the additional components of radiation and baryons, we calculate the dominant non-adiabatic modes in the radiation era and find that the modes grow in the power law with exponent at the order of unit.