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arXiv 1012.2646astro-ph.COgr-qc
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引力标量-张量理论的观测约束

Constraints on scalar-tensor theories of gravity from observations

Seokcheon Lee

备注：
19 pages, 20 figures, 2 tables, submitted to JCAP
发表信息：
JCAP 1103:021,2011
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摘要：

尽管暗能量和修正的引力理论在最初存在差异，但它们都可以用宇宙膨胀历史的有效状态方程（EOS）$ω$来参数化。Chevallier-Polarski-Linder（CPL）参数化是一种与模型无关的方法，其中的两个参数（$ω_{0}$和$ω_{a}$）可以由模型间的几何观测值约束，而这两个观测值存在退化。通常采用大尺度结构的线性生长来消除这些简并。这种生长可以通过生长指数参数$γ$来描述，并且通常可以通过$γ_{0} + γ_{a} (1 - a)$来参数化。我们使用标量张量引力理论（STG），并表明，只有当$γ_a$是不可忽略的模型之间的识别是可能的。我们发现，作为红移的函数的物质分量的线性密度扰动严重限制了STG的可行子类的$ω$和$γ$。从这个方法，我们可以排除或证明可行的STG在未来的观测。当我们使用$Z(ϕ) =1$时，$F$在可行的STG模型中显示出凸形的演化。当我们严格限制太阳系约束时，带有$Z(ϕ) = 1$的可行STG模型与暗能量模型是不可区分的。

英文摘要：

In spite of their original discrepancy, both dark energy and modified theory of gravity can be parameterized by the effective equation of state (EOS) $ω$ for the expansion history of the Universe. A useful model independent approach to the EOS of them can be given by so-called Chevallier-Polarski-Linder (CPL) parametrization where two parameters of it ($ω_{0}$ and $ω_{a}$) can be constrained by the geometrical observations which suffer from degeneracies between models. The linear growth of large scale structure is usually used to remove these degeneracies. This growth can be described by the growth index parameter $γ$ and it can be parameterized by $γ_{0} + γ_{a} (1 - a)$ in general. We use the scalar-tensor theories of gravity (STG) and show that the discernment between models is possible only when $γ_a$ is not negligible. We show that the linear density perturbation of the matter component as a function of redshift severely constrains the viable subclasses of STG in terms of $ω$ and $γ$. From this method, we can rule out or prove the viable STG in future observations. When we use $Z(ϕ) =1$, $F$ shows the convex shape of evolution in a viable STG model. The viable STG models with $Z(ϕ) = 1$ are not distinguishable from dark energy models when we strongly limit the solar system constraint.

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