arXiv 1502.009302015-02-03astro-ph.COgr-qchep-phhep-th

用耦合标量场研究暴胀和暗能量

Studies of inflation and dark energy with coupled scalar fields

Susan Vu

备注：: 199 pages, 23 figures, PhD thesis. PhD supervisor: Carsten van de Bruck

摘要：

目前，对于宇宙在早期和晚期的加速膨胀还没有明确的描述;我们知道这两个时期是暴胀和暗能量的时代。在这篇论文中包含了两个暴胀的研究和一个在暗能量的背景下。第一项研究涉及两个非正则动力学项，每个在一个两个领域的情况下，和他们的影响上产生的isocurvature模式。结果，这些项影响产生的等曲率扰动，并因此影响宇宙微波背景。在下面的研究中，我们考虑了单场和双场模型中的急剧跃迁对有效普朗克质量的影响。在这些转变所产生的原始功率谱中的一个功能被发现在单场模型中，但不是为两个场模型。最后讨论的模型是关于暗能量的。一种类型的非共形耦合检查，即“非正式”耦合，在这种情况下，一个标量场非正式耦合到物质物种。进行两次一致性检查，第一次是提供流体描述，第二次是动力学理论。由此，可观测量被构造并用于对个体耦合强度创建约束。

英文摘要：

Currently there is no definitive description for the accelerated expansion of the Universe at both early and late times; we know these two periods as the epochs of inflation and dark energy. Contained within this Thesis are two studies of inflation and one in the context of dark energy. The first study involves two noncanonical kinetic terms each in a two-field scenario, and their effects on the generation of isocurvature modes. As a result, these terms affect the isocurvature perturbations produced, and consequently the Cosmic Microwave Background. In the following study, the impact of a sharp transition upon the effective Planck mass is considered in both a single-field and two-field model. A feature in the primordial power spectrum arising from these transitions is found in single-field models, but not for two-field models. The final model discussed is on the subject of dark energy. A type of nonconformal coupling is examined namely the "disformal" coupling; in this scenario a scalar field is disformally coupled to matter species. Two consistency checks are undertaken, the first to provide a fluid description and the second, a kinetic theory. From this, observables are constructed and used to create constraints on the individual coupling strengths.

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