Exploring Strong-Field Gravity through Gravitational-Wave and Multimessenger Observations

该项目的首要目标是揭示如何通过黑洞的引力波观测和中子星的多信使观测来最终探测强，动态和非线性引力的性质。目前，用来自双黑洞合并的引力波测试广义相对论的最大挑战之一是缺乏来自广义相对论之外的理论的完整引力波形，这些理论在双演化的螺旋，合并和环缩中都是有效的。此外，对于双中子星，广义相对论的某些测试受到核物质性质不确定性的限制。PI将通过以下方式解决这些问题：（I）首次在广义相对论之外的理论中构建引力波形，这些引力波形在所有的激励合并振铃阶段都有效;（II）通过避免核物理中的不确定性，对广义相对论与中子星星观测的多信使测试进行全面研究。将要开发的引力波形模型将随时可用，并可被引力波界及其他领域广泛采用。广义相对论与中子星星观测的多信使测试非常及时，这两个项目的结果将影响物理学及其他领域的各个社区，包括引力物理学，粒子物理学，核物理学和天体物理学。该项目的长期教育目标是在全球范围内连接潜在的下一代科学家，并传达物理学的美丽和兴奋，特别是广义相对论。为了构建完整的引力波形，PI将在由弦理论激发的特定引力理论中工作，其中一些模拟已经可用。PI和合作者将为合并振铃产生更多的模拟数据，并将它们与螺旋上升期间的分析波形相结合。这些完整的波形使人们能够用现有的引力波事件更精确地探测超越广义相对论的理论，并将有助于用未来的观测来寻找新的物理学。对于多信使测试，PI将采用某些中子星星观测值之间的普遍关系，这些观测值不敏感地依赖于中子星的未知内部结构。PI将在广义相对论之外的一些理论中研究这种关系，这些理论要么引入额外的标量/矢量场，要么在高曲率区域引入修改。然后，PI将研究如何通过当前和未来的多信使观测来探测这些理论。为了实现教育目标，PI的团队将开发一款关于广义相对论和引力波的在线游戏，以吸引世界各地的年轻玩家。在游戏说明中，PI将提供对广义相对论，黑洞和引力波的简要描述，传达最近获得诺贝尔奖的物理学的兴奋和关键方面。一些学生将参与游戏开发，整合研究和教育活动。PI将公开源代码，以便任何人都可以开发自己的游戏。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The overarching goal of this project is to reveal how well one can ultimately probe the nature of strong, dynamical, and nonlinear gravity through gravitational-wave observations of black holes and multimessenger observations of neutron stars. Currently, one of the biggest challenges in testing General Relativity with gravitational waves from binary black hole coalescences is the lack of complete gravitational waveforms from theories beyond General Relativity that are valid throughout the inspiral, merger, and ringdown of the binary evolution. Moreover, for binary neutron stars, certain tests of General Relativity are limited by uncertainties in nuclear matter properties. The PI will tackle these problems by (I) constructing, for the first time, gravitational waveforms in theories beyond General Relativity that are valid in all of the inspiral-merger-ringdown phases, and (II) performing a comprehensive study of multimessenger tests of General Relativity with neutron star observations by avoiding uncertainties in nuclear physics. The gravitational waveform models to be developed will be ready to use and can be widely adopted by the gravitational wave community and beyond. Multimessenger tests of General Relativity with neutron star observations are extremely timely, and the outcome of both projects will impact various communities in physics and beyond, including gravitational physics, particle physics, nuclear physics, and astrophysics. The long-term educational goal of the project is to connect, globally, potential next-generation scientists and convey the beauty and excitement of physics, in particular General Relativity. For the construction of the complete gravitational waveforms, the PI will work in a specific gravitational theory motivated by string theory, in which some simulations are already available. The PI and collaborators will produce more simulation data for the merger-ringdown and will stitch them against analytic waveforms during the inspiral. These complete waveforms allow one to probe more precisely theories beyond General Relativity with the existing gravitational wave events and will assist in searches for new physics with future observations. For multi-messenger tests, the PI will employ universal relations among certain neutron star observables that do not depend sensitively on the unknown internal structure of neutron stars. The PI will study such relations in a few theories beyond General Relativity that either introduce additional scalar/vector fields or introduce modifications in the high curvature regime. The PI will then study how well one can probe these theories through current and future multimessenger observations. To achieve the educational goal, the PI's team will develop an online game on General Relativity and gravitational waves to reach out to young players across the world. In the game instructions, the PI will provide a brief description of General Relativity, black holes, and gravitational waves, conveying the excitement and key aspects of recent Nobel-prize winning physics. Some students will be involved in the game development, integrating the research and educational activities. The PI will make the source codes publicly available so that anyone can develop their own games.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.