Cosmology with a primordial scaling field
Cosmology with a primordial scaling field
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DOI：
10.1103/physrevd.58.023503
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发表时间：
1997-11
影响因子：
5
通讯作者：
P. Ferreira;M. Joyce
中科院分区：
文献类型：
--
作者：
P. Ferreira;M. Joyce
一个弱耦合标量场\ensuremath{\Phi}具有简单的指数势${V=M}_{P}^{4}\mathrm{exp}(\ensuremath{-}\ensuremath{\lambda}\ensuremath{\Phi}{/M}_{P})$，其中${M}_{P}$是简化的普朗克质量，$\ensuremath{\lambda}g2,$在辐射或物质主导的宇宙中有一个吸引子解，它模仿主导分量的缩放，贡献一个固定的分数${\ensuremath{\Omega}}_{\ensuremath{\varphi}}$（由\ensuremath{\lambda}决定）到能量密度。这种场一般出现在涉及紧化维度的粒子物理理论中，其值\ensuremath{\lambda}给出了与宇宙学相关的${\ensuremath{\Omega}}_{\ensuremath{\varphi}}.$对于早期宇宙中标量场的自然初始条件，吸引子解早在结构形成时代之前就建立了，与其他标量场宇宙学中使用的解相反，它不涉及标量场后期特征的能量标度。我们详细研究了在标准暴胀驱动的$\ensuremath{\Omega}=1$暗物质主导的宇宙学中物质和辐射扰动的演化。使用完整的爱因斯坦-玻尔兹曼计算，我们将可观测量与当前数据进行比较。我们发现，对于${\ensuremath{\Omega}}_{\ensuremath{\varphi}}\ensuremath{\simeq}0.08\char21{}0.12,$，这些模型与COBE探测到的大角度宇宙微波背景各向异性、星系调查汇编的线性质量方差、大爆炸核合成、丰富星系团的丰度以及Lyman- \ensuremath{\alpha}系统在高红移的约束是一致的。鉴于该模型的简单性，其理论动机及其在匹配观测中的成功，我们认为它应该与其他目前可行的结构形成模型相提并论。
A weakly coupled scalar field \ensuremath{\Phi} with a simple exponential potential ${V=M}_{P}^{4}\mathrm{exp}(\ensuremath{-}\ensuremath{\lambda}\ensuremath{\Phi}{/M}_{P})$ where ${M}_{P}$ is the reduced Planck mass, and $\ensuremath{\lambda}g2,$ has an attractor solution in a radiation or matter dominated universe in which it mimics the scaling of the dominant component, contributing a fixed fraction ${\ensuremath{\Omega}}_{\ensuremath{\varphi}}$ (determined by \ensuremath{\lambda}) to the energy density. Such fields arise generically in particle physics theories involving compactified dimensions, with values of \ensuremath{\lambda} which give a cosmologically relevant ${\ensuremath{\Omega}}_{\ensuremath{\varphi}}.$ For natural initial conditions on the scalar field in the early universe the attractor solution is established long before the epoch of structure formation, and in contrast with the solutions used in other scalar field cosmologies, it is one which does not involve an energy scale for the scalar field characteristic of late times. We study in some detail the evolution of matter and radiation perturbations in a standard inflation-motivated $\ensuremath{\Omega}=1$ dark-matter dominated cosmology with this extra field. Using a full Einstein-Boltzmann calculation we compare observable quantities with current data. We find that, for ${\ensuremath{\Omega}}_{\ensuremath{\varphi}}\ensuremath{\simeq}0.08\char21{}0.12,$ these models are consistent with large angle cosmic microwave background anisotropies as detected by COBE, the linear mass variance as compiled from galaxy surveys, big bang nucleosynthesis, the abundance of rich clusters and constraints from the Lyman-\ensuremath{\alpha} systems at high redshift. Given the simplicity of the model, its theoretical motivation and its success in matching observations, we argue that it should be taken on a par with other currently viable models of structure formation.