Modifications of Gravity and Early Universe Cosmology

为了做出可以用实验验证的预测，描述宇宙早期阶段的数学模型需要使用宇宙摄动理论。在这项研究中，学生将首先学习一个特定的引力理论，确定在早期宇宙膨胀阶段产生的线性扰动的功率谱的预测。研究了微扰的统计性质。目的是检验大的非高斯性是否也意味着功率谱不再是幂律形式。在随后的工作中，研究了早期宇宙引力的f(R)理论。这项工作将包括分析工作（特别是宇宙学摄动理论）和数值工作。

In order to make predictions which can be tested with experiments, mathematical models describing the universe it its early stages require the use of cosmological perturbation theory. In this research the student will initially study a specific theory of gravity, determine the predictions of the power spectrum of linear perturbations produced during a phase of inflation in the early universe. The statistical properties of the perturbations are also studied. The aim is to check whether large non-Gaussianities can also imply that the power spectrum to be no longer of power-law form. In subsequent work, f(R) theories of gravity of the early universe are investigated. The work will consist of both analytical work (cosmological perturbation theory in particular) and numerical work.