Probing Extreme Gravity with Gravitational Waves

引力波天体物理学已经进入了一个新的发现和探索的时代。2015年，NSF的LIGO首次探测到引力波，为引力波物理学的先驱赢得了诺贝尔奖，并获得了其他几项着名奖项。从那时起，LIGO和它的欧洲合作伙伴Virgo已经探测到了90多个其他事件。所有这些引力波都是由黑洞和/或中子星以光速的一小部分相互螺旋和碰撞发出的。所有的信号都被证明与广义相对论的预测一致，在一个以前从未被测试过的状态下：引力是巨大的，并且剧烈变化。这些物理信息的提取和解释需要精确构建引力波模型，以便将信号从探测器噪声中提取出来。该奖项的主要目标是开发现成的模型，以提取和解释偏心和进动碰撞中发射的引力波，以便这些模型可用于研究天体物理学并通过未来的观测来测试广义相对论。该奖项还利用最先进的人工智能技术，用引力波数据测试广义相对论，但事先没有规定详细的引力波模型。 该奖项将这项研究与更广泛的影响活动相结合，旨在改变K-12学生和公众对物理和科学的态度，通过该奖项在伊利诺伊大学厄巴纳-香槟分校的伊利诺伊大学高级研究中心开展的活动，这是下一代引力科学家的肥沃训练场。该奖项的目的是（i）开发轨道动力学和一般（自旋旋进和偏心）紧凑双星在inspiral期间发射的引力波的分析模型，以及（ii）使用LIGO/Virgo/KAGRA科学合作组织发布的当前公开数据进行GR的模型特定和模型不可知测试。现有的模型足以探测和表征由于自旋失调而进动的源发射的引力波，但如果轨道也是偏心的，则不足以探测和表征。LIGO已经探测到至少一个强自旋旋进的源，随着探测器升级到设计灵敏度，预计会有更多的源。该奖项构建的模型防止了由于偏心率系统学的错误建模而导致的参数估计偏差，允许提取偏心率，为天体物理学人口模型提供信息，并允许新的广义相对论测试。这项研究将通过创建参数化后爱因斯坦模型的高次谐波版本，以及通过量身定制的条件变分自动编码器创建一个全新的广义相对论人工智能测试，来增强现有和正在开发的广义相对论新理论不可知引力波测试。该奖项还实施了更广泛的影响活动，旨在改变K-12学生和公众对物理和科学的态度。 在“物理学的艺术/艺术的物理学”中，该项目教育本科生和研究生在尖端物理学方面创造传达物理学概念的艺术作品。艺术作品在一个评审展览中竞争，获胜的艺术家将成为物理学的常驻艺术家一年。在“物理事实和虚构”活动中，该项目创建了一系列简短的YouTube教育视频，纠正了公众对重力的误解。这些视频都附有漫画，形象化的物理误解和他们的决议。通过“POINT”，该奖项为中学生创造了一个新的虚拟现实模拟的分销渠道，重点是重力。虚拟现实耳机和这种模拟被带到附近的中学，并创建了关于重力的简短讲座来伴随这些模拟，所有生成的材料都可以免费在线下载。“GW Artisan”是一本介绍引力波物理学及其在天体物理学、宇宙学、核物理学和理论物理学中的应用的书，面向高年级本科生和年轻的研究生。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。

Gravitational wave astrophysics has entered a new era of discovery and exploration. In 2015, NSF's LIGO detected gravitational waves for the first time, earning the pioneers of gravitational wave physics a Nobel prize, and the collaboration several other prestigious prizes. Since then, LIGO and its European partner, Virgo, have detected over 90 other events. All of these gravitational waves were emitted by black holes and/or neutron stars inspiraling and colliding against each other, at a high fraction of the speed of light. All signals were shown to be consistent with the predictions of general relativity in a regime that had never been tested before: where the gravitational force is enormous and violently changing. The extraction of this physical information and interpretation required the accurate construction of gravitational wave models with which to pull the signal out of the detector noise. The main objective of this award is to develop ready-to-use models to extract and interpret gravitational waves emitted in eccentric and precessing collisions, so that these models can be used to study astrophysics and test general relativity with future observations. The award also leverages state-of-the-art artificial intelligence techniques to test general relativity with gravitational wave data but without prescribing a detailed gravitational wave model beforehand. The award integrates this research with broader impact activities, aimed at changing the attitudes of K-12 students and the general public toward physics and science through activities the award develops in the Illinois Center for Advanced Studies of the University at the University of Illinois Urbana-Champaign, a fertile training ground for the next generation of gravitational scientists. This award is aimed at (i) developing analytic models for the orbital dynamics and the gravitational waves emitted by generic (spin-precessing and eccentric) compact binaries during inspiral, and (ii) carrying out model-specific and model-agnostic tests of GR using current public data released by the LIGO/Virgo/KAGRA Scientific Collaboration. Existing models are sufficient for the detection and characterization of gravitational waves emitted by sources that are precessing due to spin misalignment, but not if the orbits are also eccentric. LIGO has already detected at least one source that is strongly spin-precessing, and more are expected as detectors are upgraded to reach design sensitivity. The model this award constructs prevents parameter estimation biases because of mismodeling eccentricity systematics, allowing for the extraction of eccentricity, informing astrophysical population models and allowing new general relativity tests. This research will enhance existing and developing new theory-agnostic gravitational-wave tests of general relativity, by creating a higher-harmonics version of the parameterized post-Einsteinian model, and by creating a brand-new artificial-intelligence-enabled test of general relativity through a tailor-made conditional variational auto-encoder. This award also implements broader impact activities aimed at changing the attitudes of K-12 students and the general public toward physics and science. In "The Art of Physics/The Physics of Art", the project educates undergraduate and graduate students in cutting-edge physics to create art works that convey physics concepts. The art pieces compete at a juried exhibition, with the winning artist becoming the resident artists in physics for one year. In the "Physics Facts and Fictions" activity, the project creates a series of short, educational YouTube videos, which correct misconceptions about gravity for the general public. The videos are accompanied by cartoons that visualize the physics misconceptions and their resolutions. Through "POINT", the award creates a distribution channel for a new virtual reality simulation for middle school students that focuses on gravity. Virtual reality headsets and this simulation are taken on the road to nearby middle schools, and short lectures on gravity are created to accompany these simulations, with all material generated becoming freely available to download online. The "GW Artisan” is a book that introduces gravitational-wave physics, and its applications to astrophysics, cosmology, nuclear physics and theoretical physics, to advanced undergraduate and young graduate students.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.