Instrumentation and Simulation for Advanced LIGO Upgrades and Future Gravitational Wave Detectors

该奖项支持相对论和相对论天体物理学的研究，并解决了NSF“宇宙之窗”大构想的优先领域。近年来引力波探测领域的影响是难以夸大的。高级LIGO探测器的结果经常引起公众的想象，成为头条新闻，同时为科学知识前沿的研究提供重要的新数据。对双黑洞系统的定期探测使科学家们能够编制一份以前不为人知的天体目录。对探测到的事件产生的引力波的精确测量，使我们能够探索支撑我们对宇宙理解的基本理论的细节。该奖项支持的工作直接旨在提高未来LIGO探测器的灵敏度，以及开发下一代引力波探测器的技术和设计。这些目标将以不断的发现和更好的科学产品的形式产生直接回报。长期以来，美国一直被认为是引力波天文学领域的领导者。为了在接下来的几十年里保持这一地位，有必要继续研究以推动引力波探测器的可能边界。该奖项支持的大部分工作将由研究生和本科生完成，为他们提供良好的培训机会，以发展他们的技能，从而丰富未来的美国科学劳动力。这项研究的主题也是向更广泛的公众宣传的一个非常肥沃的土壤，这是扩大全社会参与科学的最佳途径之一。该奖项支持模拟和实验项目组件。仿真组件旨在表征先进LIGO干涉仪的低频（30Hz）噪声，并利用所获得的知识为未来升级的设计提供信息。表征低频探测器噪声是非常具有挑战性的，因为它是许多单个噪声源的组合，而且因为即使是这些单个噪声源也是交叉耦合的，很难建模和估计。然而，新的模拟工具正在开发中，能够解决这些噪声的影响，本项目将应用这些工具来解决这个问题。在接下来的两次观测运行中，同样的工具也将用于支持高级LIGO探测器的调试，这两次观测都将包括对干涉仪的新硬件和配置升级。该项目的实验部分包括开发一种新的方法来检测激光干涉仪中的不对准和其他光学缺陷，该方法比目前使用的方案具有一些实际优势。在桌面激光干涉实验中，将对不同的方法进行详细的比较，以便为未来引力波探测器的设计选择提供信息。此外，该项目还将通过实验证明新型光束形状（高阶厄米-高斯模式）的干涉性能，这有可能减少激光干涉仪中一种基本噪声源的影响：热噪声。该奖项反映了美国国家科学基金会的法定使命，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。

This award supports research in relativity and relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. The impact of the field of gravitational wave detection in recent years is difficult to overstate. Results from the Advanced LIGO detectors have regularly captured the imagination of the public, making headline news while providing vital new data to enable studies at the forefront of scientific knowledge. Regular detections of binary black hole systems have allowed scientists to compile a catalog of previously unknowable celestial objects. Precise measurements of the gravitational waveforms from the detected events allow us to probe the details of fundamental theories underpinning our understanding of the universe. The work supported by this award is directly aimed at improving the LIGO detector sensitivity in the future, as well as developing technology for and informing the design of the next generation of gravitational wave detectors. These goals will have a direct payoff in the form of continued discoveries and better science products. The USA has long been recognized as a leader in the field of gravitational wave astronomy. Continued research to push the boundaries of what is possible with gravitational wave detectors is necessary to maintain this position over the next decades. The majority of the work supported by this award will be performed by graduate students and undergraduate students, providing them with excellent training opportunities to develop their skills, therefore enriching the future American scientific workforce. The subject of the research is also a very fertile ground for outreach to the wider public, which is one of the best ways to broaden participation in science across society.This award supports both simulation and experimental project components. The simulation component is aimed at characterizing the low frequency (30Hz) noise of the Advanced LIGO interferometers, and using the knowledge gained to inform the design of future upgrades. Characterizing the low frequency detector noise is very challenging because it is a combination of many individual noise sources, and because even these individual noise sources are cross-coupled and difficult to model and estimate. However, new simulation tools are being developed that have the capability to untangle these noise contributions, and this project will apply these tools to tackle this problem. The same tools will also be used to support commissioning of the Advanced LIGO detectors in the lead up to the next two observing runs, both of which will include new hardware and configuration upgrades to the interferometers. The experimental component of this project includes the development of a new method for sensing misalignment and other optical imperfections in laser interferometers, which has some practical advantages over the currently used schemes. Detailed comparisons will be made between the different methods in tabletop laser interferometry experiments, in order to inform design choices for the gravitational wave detectors of the future. Also supported is a project to experimentally demonstrate the interferometric performance of new beam shapes (higher-order Hermite-Gauss modes), which have the potential to reduce the impact of one of the fundamental noise sources in laser interferometers: thermal noise.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.