GR Dynamics of Stochastic Inflation

随机通货膨胀的 GR 动力学

• 批准号: 2758438
• 金额: --
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2758438
• 关键词: GR; Dynamics; Stochastic; Inflation

This PhD project will advance the early universe theory of inflation, which explains the origin of galaxies and large-scale structure in the Universe, by merging stochastic inflation methods with fully nonlinear General relativistic evolution to make quantitative statistical predictions from inflationary models. Non-Gaussian signatures are inherently present in primordial fluctuations due to the nonlinearities produced by both general relativity and the fact that the potential responsible for driving inflation may be interacting. The goal of this project is to analytically and numerically model nonlinear inflationary dynamics in order to make bispectrum (three-point) and other higher-order correlator predictions which encompass a much broader range of inflationary scenarios (including those with multiple fields); this is an important discriminant between competing inflation models that can be used to distinguish them observationally. This will be achieved by exploiting the new GRChombo numerical relativity pipeline to compute these nonlinear effects using full 3D general relativistic simulations, augmenting it by the inclusion of quantum fluctuations that get amplified during Inflation. The latter will be implemented as stochastic source terms to be integrated within the GRChombo evolution routines and which, in turn, will be determined via perturbative analytic computations from effective field theory. DAMTP cosmologists, led by the PhD supervisor Shellard, have been able to constrain a wide range of inflationary scenarios by using innovative separable techniques (the MODAL pipeline) to extract and reconstruct the temperature and polarization bispectra from Planck satellite maps of the cosmic microwave background (CMB); this is now being applied to new observational data sets from both CMB experiments (Simons Observatory) and galaxy surveys (SDSS, DES and beyond). The resulting 3D fields of the stochastic nonlinear GR simulations from this PhD project will be directly amenable to analysis by these techniques, advancing the detailed confrontation of inflationary theory with cosmological data

该博士项目将推进早期宇宙暴胀理论，通过将随机暴胀方法与完全非线性的广义相对论演化相结合，从暴胀模型中进行定量统计预测，解释宇宙中星系和大尺度结构的起源。由于广义相对论产生的非线性以及驱动通货膨胀的潜力可能相互作用的事实，非高斯特征本质上存在于原始波动中。该项目的目标是对非线性通胀动力学进行分析和数值建模，以便进行双谱（三点）和其他高阶相关器预测，其中涵盖更广泛的通胀场景（包括具有多个场的场景）；这是竞争性通货膨胀模型之间的重要区别，可用于在观察上区分它们。这将通过利用新的 GRChombo 数值相对论管道，使用完整的 3D 广义相对论模拟来计算这些非线性效应，并通过包含在暴胀期间放大的量子波动来增强它来实现。后者将作为随机源项实现，集成到 GRChombo 演化例程中，而随机源项又将通过有效场理论的微扰分析计算来确定。由博士生导师 Shellard 领导的 DAMTP 宇宙学家已经能够通过使用创新的可分离技术（MODAL 管道）从宇宙微波背景 (CMB) 的普朗克卫星图中提取和重建温度和偏振双谱来限制各种暴胀情景；现在，该技术正应用于来自 CMB 实验（西蒙斯天文台）和星系巡天（SDSS、DES 等）的新观测数据集。该博士项目产生的随机非线性 GR 模拟的 3D 场将直接适合通过这些技术进行分析，从而推进暴胀理论与宇宙学数据的详细对抗