The Origin of Matter in the Universe

宇宙物质的起源

• 批准号: 0757746
• 负责人: Gary Felder
• 金额: $ 10.5万
• 依托单位: Smith College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0757746&HistoricalAwards=false
• 关键词: Origin; Matter; Universe

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.

早期宇宙中从膨胀结束到热化等离子体形成的短暂时期是宇宙学中最不为人所知的时代之一。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尚不清楚，并且对再加热进行建模需要大规模数值计算。 PI 与他人共同创作了 LATTICEEASY，这是使用最广泛的模拟再加热时代的程序。然而，迄今为止的大多数模拟都仅限于相互作用标量场的不切实际的简单模型。 PI 打算扩展其代码的功能，使其能够在并行处理器集群上运行，并在计算中包含规范字段。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。了解预热很重要，因为它引入了额外的“手柄”（引力波、拓扑缺陷），人们可以用这些“手柄”来约束膨胀所涉及的物理现象。与暴胀物理相关的其他可观测量（例如宇宙微波背景）对暴胀模型提供了约束，但本质上并没有告诉我们任何有关暴胀子如何与其他场耦合的信息。如果我们要超越暴胀唯象模型并真正开始讨论将暴胀子嵌入到能够与粒子物理其他领域联系的模型中，那么有关耦合的信息将至关重要。 PI 打算开发一个项目来培训本科生进行数值计算。这将包括让本科生研究助理参与编写和运行数值模拟，为史密斯物理专业的两门必修课程创建计算单元，并围绕 PI 宇宙学研究中的示例开发一门计算课程。