Observational tests of past and present inflation

宇宙学观测有利于宇宙在其历史上经历两个加速膨胀时期。一种被称为膨胀的现象被认为发生在遥远的过去，有助于解释所观察到的宇宙的大尺度特征。另一个加速期正在进行中，根据我们目前的模型，宇宙密度的70%需要以暗能量的形式存在。但这两种现象在基础理论方面仍然缺乏令人满意的描述。建议的研究将有助于开发膨胀和暗能量的模型和用观测来检验它们的方法。它将帮助培养学生在一个快速发展的领域，并进一步加强加拿大作为基础研究领导者的地位。布莱恩膨胀场景是如何在弦理论框架内实现膨胀的一个实际例子-弦理论是所有粒子相互作用基本理论的领先候选者。可能有助于将布莱恩膨胀与其他膨胀模型区分开来的是一种特殊类型的宇宙弦，这种弦形成于膜-反膜碰撞中。我将研究这些弦网络的非平凡性质，并确定它们的可观测特征，例如它们将在宇宙微波背景辐射中诱导的信号。宇宙加速可能是由某种类型的排斥暗能量引起的，也可能是引力在最大尺度上服从不同定律的表现。我的工作将包括开发暗能量测试，以最大限度地利用数据中包含的信息。我还将研究一些有趣的修正引力模型，重点放在它们对宇宙物质聚集的预测上。未来的望远镜将能够追踪宇宙结构的演变。我的研究包括理解计划的和提议的观察的能力，并对它们将在多大程度上帮助我们区分不同的理论做出详细的预测。

Cosmological observations favor a universe with two periods of accelerated expansion in its history. One, known as Inflation, is thought to have happened in the distant past and helps explain the observed large scale features of the universe. The other period of acceleration is ongoing and, according to our current model, requires 70% of the universe density to be in the form of Dark Energy.  Both phenomena are still lacking a satisfactory description in terms of a fundamental theory.  The proposed research will contribute to developing models of Inflation and Dark Energy and ways of testing them with observations. It will help train students in a rapidly developing field, and further strengthen Canada's position as a leader in fundamental research.The Brane Inflation scenario is a working example of how inflation can be realized within the framework of String Theory -- a leading candidate for a fundamental theory of all particle interactions. What may help to distinguish Brane Inflation from other inflationary models is the special type of cosmic strings that form in brane-anti-brane collisions. I will study the non-trivial properties of these string networks and identify their observable features, such as the signatures they would induce in the cosmic microwave background radiation.The cosmic acceleration could be caused by some type of repulsive Dark Energy or be a manifestation of Gravity obeying different laws on largest scales. My work will include developing tests of Dark Energy that will maximally utilize the information contained in the data. I will also study some of the interesting models of modified gravity with the focus on their predictions for the clustering of cosmic matter. Future telescopes will be able to track the evolution of cosmic structures back in time. My research involves understanding the capabilities of planned and proposed observations and making detailed forecasts of the extent to which they will help us be distinguish between different theories.