标题： 精确和扰动弗里德曼-勒梅特宇宙学 显示英文标题

标题： Exact and Perturbed Friedmann-Lemaitre Cosmologies

摘要： 在本论文中，我们首先应用广义相对论的1+3协变描述来分析n流体弗里德曼-勒梅特（FL）宇宙学；即，物质能量内容由n个非相互作用流体组成的均匀且各向同性的宇宙学。 我们受到研究这种类型的FL模型的激励，因为观测表明物理宇宙接近于由包含辐射、尘埃和宇宙常数的物质内容所描述的FL模型。 其次，我们使用1+3协变描述来分析包含完美流体和宇宙常数的FL宇宙学的标量、矢量和张量扰动。 特别是，我们对尘埃或辐射背景下的扰动行为进行了详尽的讨论。 显示英文摘要

摘要： In this thesis we first apply the 1+3 covariant description of general relativity to analyze n-fluid Friedmann-Lemaitre (FL) cosmologies; that is, homogeneous and isotropic cosmologies whose matter-energy content consists of n non-interacting fluids. We are motivated to study FL models of this type as observations suggest the physical universe is closely described by a FL model with a matter content consisting of radiation, dust and a cosmological constant. Secondly, we use the 1+3 covariant description to analyse scalar, vector and tensor perturbations of FL cosmologies containing a perfect fluid and a cosmological constant. In particular, we provide a thorough discussion of the behaviour of perturbations in the physically interesting cases of a dust or radiation background.