The A+ Upgrade to Advanced LIGO

在过去的两年里，NSF支持的LIGO实验室打开了宇宙的引力波窗口，并建立了引力波支持的多信使天体物理学的全新领域。 这些革命性的成就是由亚attometer位置测量技术实现的，该技术通过Advanced LIGO探测器在多公里的基线上实现。 这一新举措，即“A+升级”，可以提供比现有先进LIGO设计高五倍的引力波事件探测率。除其他科学目标外，A+所提供的增强能力将能够阐明恒星质量黑洞的起源和演化，允许对极端引力进行精确测试，能够详细研究中子星的状态方程，并允许对宇宙学进行新的测试，包括对哈勃常数的完全独立的约束。 A+升级还将促进扩大社区参与，增加教育机会和公众对科学的理解。A+的目标是LIGO技术的两个方面，预计将引起不同社区的浓厚兴趣，包括量子光学，量子信息理论，材料科学，光学技术，精密计量和物理标准。A+的升级解决了限制先进LIGO设计目标灵敏度的两个技术限制：量子力学不确定性和反射镜涂层中的经典布朗噪声。改进后的A+仪器将在2024年年中达到观测准备状态，使LIGO能够继续领导全球开放和利用这种新观测模式的努力。A+计划建立在成功交付Advanced LIGO的联合国际团队的专业知识和协同作用的基础上。 大约35%的A+硬件将由英国和澳大利亚的LIGO科学合作组织（LSC）提供，沿着，英国和澳大利亚的工作人员将做出重大努力。这些投资是对英国科学技术设施理事会（STFC）和澳大利亚研究理事会（ARC）对Advanced LIGO做出的重要和非常成功的贡献的回应。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。

Over the past two years, the NSF-supported LIGO Laboratory has opened the gravitational-wave window on the universe and established the entirely new field of gravitational-wave-enabled multi-messenger astrophysics. These revolutionary achievements were enabled by sub-attometer position measurement technologies made possible over multi-kilometer baselines through the Advanced LIGO detector. This new initiative, the "A+ upgrade", can offer five times the gravitational wave event detection rate over the existing Advanced LIGO design. The enhanced capabilities afforded by A+ will be able to, among other science goals, illuminate the origins and evolution of stellar-mass black holes, allow precision tests of extreme gravity, enable detailed study of the equation of state of neutron stars, and permit new tests of cosmology, including fully independent constraints on the Hubble constant. The A+ upgrade will also foster expanding community participation and enhance opportunities for education and public understanding of science. Both aspects of LIGO technology targeted by A+ are expected to be of keen interest to diverse communities, including quantum optics, quantum information theory, materials science, optical technology, precision metrology and physical standards.The A+ upgrade addresses two technical limitations that have constrained the Advanced LIGO design target sensitivity: quantum mechanical uncertainty and classical Brownian noise in mirror coatings. The improved A+ instruments should reach observational readiness as soon as mid-2024, enabling LIGO to continue its leadership of the worldwide effort to open and exploit this new mode of observation. The A+ plan builds on the expertise and synergy of the joint international team that successfully delivered Advanced LIGO. Approximately 35% of A+ hardware will be contributed by UK and Australian LIGO Scientific Collaboration (LSC) groups, along with significant commitments of effort by UK and Australian personnel. These investments echo the crucial and highly successful UK Science and Technology Facilities Council (STFC) and Australian Research Council (ARC) contributions made to Advanced LIGO.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.