The Origin of Matter in the Universe

早期宇宙中从膨胀结束到热化等离子体发展的短暂时期是宇宙学中最不了解的时期之一。在那个被称为“再加热”的时代，我们今天看到的粒子、场和有效的低能相互作用都得到了发展，但描述那个时间所需的高能物理学尚不清楚，建模再加热需要大规模的数值计算。PI与人合著了LATTICEASY，这是用于模拟再加热时代的最广泛使用的程序。然而，迄今为止，大多数模拟都局限于不切实际的相互作用标量场的简单模型。PI打算扩展他的代码的能力，使其在并行处理器集群上运行，并在其计算中包括规范场。利用这些扩展功能，他将模拟高能物理复杂模型中的再加热，并提取可测试的预测。理解预热是很重要的，因为它引入了额外的“把手”（引力波，拓扑缺陷），人们可能会用它来约束暴胀中涉及的物理学。其他与暴胀物理学相关的观测量，如CMB，为暴胀模型提供了限制，但就其性质而言，它们并没有告诉我们暴胀子如何与其他场耦合。如果我们要超越暴胀的唯象模型，真正开始讨论将暴胀子嵌入一个能够与粒子物理学其他领域接触的模型，那么关于耦合的信息将是至关重要的。 PI打算开发一个培训本科生数值计算的程序。这将包括涉及本科研究助理在写作和运行数值模拟，创建计算单元的两个史密斯物理学专业的必修课程，并制定了一个关于计算的过程中建立周围的例子从PI的宇宙学研究。

The brief period in the early universe from the end of inflation until the development of a thermalized plasma is one of the least understood eras in cosmology. During that era, which is known as "reheating," the particles, fields, and effective low-energy interactions we see today all developed, but the high-energy physics required to describe that time is not known and modeling reheating requires large-scale numerical computations. The PI has coauthored LATTICEEASY, the most widely used program for simulating the reheating era. Most simulations to date, however, have been limited to unrealistically simple models of interacting scalar fields. The PI intends to extend the capabilities of his code to run on clusters of parallel processors and to include gauge fields in its calculations. Using those extended capabilities he will simulate reheating in complex models of high-energy physics and extract testable predictions. An understanding of preheating is important because it introduces extra "handles" (gravitational waves, topological defects) that one might use to constrain the physics involved in inflation. Other observables related to inflationary physics such as the CMB provide constraints on inflation models, but by their nature don't tell us anything about how the inflaton couples to other fields. Information about the couplings will be crucial if we are to move beyond phenomenological models of inflation and really start talking about embedding the inflaton in a model capable of making contact with other areas of particle physics. The PI intends to develop a program for training undergraduate students in numerical computation. This will include involving undergraduate research assistants in writing and running numerical simulations, creating computational units for two of the required courses in the Smith physics major and developing a course on computation built around examples drawn from the PI's cosmological research.