Observational constraints on generalized Proca theories
Observational constraints on generalized Proca theories
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DOI：
10.1103/physrevd.95.123540
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发表时间：
2017-03
影响因子：
5
通讯作者：
A. D. Felice;Lavinia Heisenberg;S. Tsujikawa
中科院分区：
文献类型：
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作者：
A. D. Felice;Lavinia Heisenberg;S. Tsujikawa
在广义Proca理论框架下的晚期宇宙加速模型中，存在一个de Sitter吸引子，其前面是暗能量状态方程w_{\rmDE}=-1-s$，其中s$为正常数。我们用Markov-Chain-蒙特-卡罗程序对宇宙微波背景、重子声振荡、Ia型超新星和哈勃膨胀率的观测数据进行了验证，得到了在95%置信水平下的边界s=0.254^{{}+ 0.118}-0.097}。在$\Lambda$-冷暗物质（$\Lambda$CDM）模型中引入额外的参数s$，可以减少宇宙微波背景辐射和低红移测量之间哈勃常数H_0 $的紧张关系。考虑到星系功率谱中红移空间畸变的宇宙增长数据，并考虑到无鬼和宇宙学扰动的稳定性条件，我们发现s的边界移动到了s=0.16^{+0.08}-0.08}（95%CL），因此s>0的模型仍然优于Lambda CDM模型.除了数量$s，H_0$和今天的物质密度参数$\Omega_{m0}$，与扰动相关的其他模型参数的约束不那么严格，反映了这样一个事实，即有不同的参数集，引起了类似的宇宙膨胀和增长的历史。
In a model of the late-time cosmic acceleration within the framework of generalized Proca theories, there exists a de Sitter attractor preceded by the dark energy equation of state $w_{\rm DE}=-1-s$, where $s$ is a positive constant. We run the Markov-Chain-Monte-Carlo code to confront the model with the observational data of Cosmic Microwave Background (CMB), baryon acoustic oscillations, supernovae type Ia, and local measurements of the Hubble expansion rate for the background cosmological solutions and obtain the bound $s=0.254^{{}+ 0.118}_{{}-0.097}$ at 95% confidence level (CL). Existence of the additional parameter $s$ to those in the $\Lambda$-Cold-Dark-Matter ($\Lambda$CDM) model allows to reduce tensions of the Hubble constant $H_0$ between the CMB and the low-redshift measurements. Including the cosmic growth data of redshift-space distortions in the galaxy power spectrum and taking into account no-ghost and stability conditions of cosmological perturbations, we find that the bound on $s$ is shifted to $s=0.16^{+0.08}_{-0.08}$ (95 % CL) and hence the model with $s>0$ is still favored over the $\Lambda$CDM model. Apart from the quantities $s, H_0$ and the today's matter density parameter $\Omega_{m0}$, the constraints on other model parameters associated with perturbations are less stringent, reflecting the fact that there are different sets of parameters that give rise to a similar cosmic expansion and growth history.