The Origin of Matter in the Universe: Nonequilibrium Field Theory and Inflationary Cosmology

现代宇宙学和粒子物理学的最大挑战之一是解释宇宙中物质的起源。形成星系、恒星和最终生物的物质是如何起源于大爆炸模型所描述的原始火球的？一旦有了组成粒子物理标准模型的轻子、夸克和规范场，大爆炸宇宙学就非常成功地解释了第一个轻核和原子的形成。挑战在于理解标准模型本身产生粒子的机制：它们的起源和无处不在的物质相对于反物质的过剩。观测结果坚定地支持这样的观点，即早期宇宙经历了一段短时间的超光速(指数)膨胀，即所谓的暴涨。物质的起源可以追溯到这个通货膨胀时代的结束，当时推动通货膨胀的原始场将其能量转移到物质场。这种转变是戏剧性的：它有效地模拟了热的大爆炸，并被认为至少经历了两个阶段，即预热和再热。这一提议的目标是解决物质的起源及其在膨胀过渡到炽热的大爆炸模型时相对于反物质的过剩。PI计划利用非平衡场理论的分析和数值技术，对各种模型的预热和再加热阶段的非摄动动力学进行详细分析。基于这一分析，PI希望为不同的模型提出几个预热/再热的观测结果，包括：e折叠的数量或通胀阶段的有效性；净重子数的产生；以及引力波随机背景的产生。

One of the greatest challenges of modern cosmology and particle physics is to explain the origin of matter in the Universe. How did the matter that makes galaxies, stars, and ultimately living beings originate in the primeval fireball described by the Big Bang model? Once the ingredients are there the leptons, quarks, and gauge fields comprising the Standard Model of particle physics Big Bang cosmology is very successful at explaining the formation of the first light nuclei and atoms. The challenge lies in understanding the mechanisms responsible for generating the particles of the Standard Model themselves: their origin and the ubiquitous excess of matter over antimatter. Observations firmly support the notion that the early Universe underwent a short period of superluminal (exponential) expansion known as inflation. The origin of matter is traced to the end of this inflationary era, when the primordial field that drives inflation transfers its energy into matter fields. This transfer is dramatic: it effectively models the hot Big Bang and is believed to have occurred in at least two phases, known as preheating and reheating. The goal of this proposal is to address both the origin of matter and its excess over antimatter as inflation transitions into the hot Big Bang model. The PI plans to analyze in detail the nonperturbative dynamics of the preheating and reheating stages for a variety of models, using analytical and numerical techniques of nonequilibrium field theory. Based on this analysis, the PI hopes to propose several observational consequences of pre/reheating for different models, including: the number of e-folds or efficacy of the inflationary phase; the generation of net baryon number; and the production of a stochastic background of gravitational waves.