Experiments and Simulations for Improving the Sensitivity of Advanced LIGO and Future Gravitational Wave Detectors

2015年，Advanced LIGO首次探测到引力波，标志着引力波天文学时代的到来。从那时起，高级LIGO继续提供对我们宇宙本质的迷人洞察；证实了几个合并的黑洞双星系统的存在，以及在电磁观测的同时探测到来自中子星的引力波。尽管取得了这些令人难以置信的成就(包括诺贝尔物理学奖)，高级LIGO还没有以预期的最高灵敏度运行。该奖项支持以实验和模拟的形式进行研究，以提高先进LIGO的灵敏度，目的是更频繁地探测引力波事件，并具有更高的信噪比。更高灵敏度的观测将增加观测运行的科学产量，使我们能够对引力的性质、中子星的组成以及我们宇宙中黑洞的形成历史做出更有力的陈述。该奖项还支持对超越高级LIGO的引力波探测器技术的研究，以便科学界做好准备，以尽可能最佳的设计和组件建造未来的探测器。大部分支持的工作将由本科生、研究生和新近毕业的博士完成。这将为这些初级科学家提供一个极好的培训机会，使他们能够获得宝贵的技能和经验，同时也有助于加强美国的科学队伍。该奖项支持几个旨在开发特定技术的实验计划，这些技术可能用于高级LIGO和未来的引力波探测器。所有干涉式引力波探测器都采用方案来管理探测测试质量位置的激光束中的波前失真，这可能会在几个方面限制探测器的灵敏度。随着压缩光技术的应用，波前失真将变得更加严重，以降低探测器的量子噪声限制。将开展一项实验计划，以研究在这些失真出现时检测它们的新方法，以便在它们对探测器灵敏度产生负面影响之前纠正它们。根据该奖项执行的另一项实验计划将开发一种新的对准传感技术，该技术有可能简化引力波探测器的光学布局，并减少未对准驱动的噪声。还将进行一项实验研究，以确定使用非传统激光光束形状的可行性，以减少镜面热噪声对干涉仪灵敏度的影响。该奖项还支持开发和使用激光干涉仪模拟工具，以表征和改进高级LIGO探测器的操作。在理解干涉仪中的极限噪声源方面，模拟通常起着关键作用，并且可用于在实际探测器中实施通常昂贵且耗时的潜在解决方案之前对其进行快速测试。根据该奖项开展的工作还将超越Advanced LIGO，着眼于近期升级和更长期的新探测器，使用类似的模拟来帮助设计和优化这些新的、更灵敏的机器。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The first detection of gravitational waves by Advanced LIGO in 2015 marked the dawn of the era of gravitational wave astronomy. Since then Advanced LIGO has continued to provide fascinating insights into the nature of our universe; confirming the existence of several merging black hole binary systems, as well as detecting gravitational waves from a neutron star inspiral and merger in parallel with electromagnetic observations. In spite of these incredible achievements (recognized with awards including the Nobel Prize in Physics), Advanced LIGO is not yet operating at its predicted maximum sensitivity. This award supports research in the form of experiments and simulations towards improving the sensitivity of Advanced LIGO, with the aim of detecting gravitational wave events more often and with higher signal-to-noise ratios. Higher sensitivity observations will increase the scientific yield of observing runs, allowing us to make stronger statements about the nature of gravity, the composition of neutron stars, and the formation history of black holes in our universe. This award also supports research into technology for gravitational wave detectors beyond Advanced LIGO, so that the scientific community can be prepared to build the detectors of the future with the best possible design and components. Much of the supported work will be performed by undergraduate students, postgraduate students and recent PhD graduates. This will provide an excellent training opportunity for these junior scientists, allowing them to gain valuable skills and experience, while also serving to bolster the scientific workforce in the USA.This award supports several experimental programs aimed at developing specific technologies for potential use in Advanced LIGO and future gravitational wave detectors. All interferometric gravitational wave detectors employ schemes to manage wavefront distortions in the laser beams that probe the position of the test masses, which can limit the sensitivity of detectors in several ways. Wavefront distortions will become even more critical as squeezed light technology is employed in order to reduce the quantum noise limit of the detectors. An experimental program will be carried out to investigate new ways to sense these distortions as they arise, in order that they can be corrected before they negatively impact the detector sensitivity. Another experimental program performed under this award will develop a new alignment sensing technique, which has the potential to simplify the optical layout of gravitational wave detectors and reduce the misalignment driven noise. An experimental investigation will also be pursued to determine the feasibility of using non-traditional laser beam shapes in order to reduce the effects of mirror thermal noise on interferometer sensitivity. This award also supports the development and use of laser interferometer simulation tools for characterizing and improving the operation of the Advanced LIGO detectors. Simulations have often played a key role in understanding the limiting noise sources in interferometers, and can be used to provide rapid tests of potential solutions before their often costly and time-intensive implementation in real detectors. The work performed under this award will also look beyond Advanced LIGO to near-term upgrades and longer-term new detectors, using similar simulations to help in the design and optimization of these new, more sensitive machines.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.