Measuring Gravity at the Micron Scale with Laser-Cooled Trapped Microspheres: a Continuation

该奖项由引力物理和原子，分子和光学实验物理计划支持。引力是迄今为止人们最不了解的基本自然力。一个特别的谜团是，为什么引力比自然界中的其他标准模型力弱得多。正如最近的一些理论所表明的那样，通过测量重力在亚毫米距离上的行为，可以获得与这个“层次问题”有关的重要线索。这样的测量可能会导致标准模型之外令人兴奋的物理学新发现。然而，大质量物体之间的引力随着它们的尺寸和分离距离的减小而迅速变弱，因此在亚毫米长度尺度上进行超灵敏测量是必要的。这个小组正在开发一个基于新技术的实验，它可以在微米尺度上将我们对重力的理解提高几个数量级。在这种方法中，熔融石英测试质量悬浮在由光制成的“容器”中，从而大大降低摩擦并提高灵敏度。从事该项目的学生和博士后研究人员将在实验物理和纳米纤维方面接受广泛的培训，并将为进入科学劳动力市场做好准备。这个项目的基本性质吸引了我们对自然世界的好奇心。 国家将受益于在微米尺度上对与引力物理学相关的高能物理学的更好理解，而粒子对撞机实验的成本仅为一小部分。该奖项支持一项实验，该实验使用激光冷却的捕获微球来测试微米尺度上与牛顿引力的Yukawa型偏差。通过光学悬浮力传感器，从环境中精确解耦是可能的，在室温下产生低于aN-Hz^1/2的力灵敏度。这项新技术最终可以将我们对微米尺度重力的理解提高1,000到100,000倍，并可能导致突破性的发现。除了短程引力的研究，拟议的实验技术也将使新的调查卡西米尔力在未探索的制度。该项目在概念上分为三个任务：（1）改进技术，将悬浮纳米球定位在距离源质量表面几微米的距离内，（2）初步重力测量的系统误差调查，（3）并行开发捕获和冷却悬浮纳米颗粒的新方法，包括冷原子的共振冷却。一名研究生，一名本科生和一名博士后研究员将接受实验物理和纳米纤维的广泛培训，并鼓励他们在科学会议上展示结果。通过参与这个高度跨学科的研究项目，学生将为科学事业做好准备。该奖项反映了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 is supported by the Gravitational Physics and the Atomic, Molecular and Optical Experimental Physics programs. Gravity is by far the least understood fundamental force of nature. One particular mystery has to do with why gravity is so much weaker than the other Standard Model forces in nature. As a number of recent theories have suggested, important clues related to this "hierarchy problem" can be obtained by measuring how gravity behaves at sub-millimeter distances. Such measurements could lead to exciting new discoveries of physics beyond the Standard Model. However, the gravitational force between massive objects becomes weak very rapidly as their size and separation distance decreases, thus making ultra-sensitive measurements a necessity at sub-millimeter length scales. This group is developing an experiment based on new technology which could advance our understanding of gravity by several orders of magnitude at the micrometer length scale. In this approach, a fused silica test mass is suspended in a "container" made of light, leading to greatly reduced friction and enhanced sensitivity. The students and postdoctoral researchers working on this project will be broadly trained in experimental physics and nanofabrication and will be well positioned for entry into the scientific workforce. The fundamental nature of this project appeals to our sense of wonder about the natural world. The nation will benefit from an improved understanding of high-energy physics related to gravitational physics at the micron-length scale, at a fraction of the cost of particle-collider experiments.This award supports an experiment which uses laser-cooled trapped microspheres to test for Yukawa-type deviations from Newtonian gravity at the micron length scale. By optically levitating the force sensor, an exquisite de-coupling from the environment is possible, yielding sub aN-Hz^1/2 force sensitivity at room temperature. This new technique could ultimately advance our understanding of gravity at the micron length scale by a factor of 1,000 to 100,000, and may lead to ground-breaking discoveries. In addition to studies of short-range gravitational forces, the proposed experimental technique will also enable novel investigations of Casimir forces in unexplored regimes. The project is conceptually divided into three tasks: (1) refinement of techniques to position levitated nanospheres within few-micron distances from a source mass surface, (2) investigation of systematic errors in preliminary gravity measurements, (3) in-parallel development of novel methods for trapping and cooling the levitated nanoparticles, including sympathetic cooling with cold atoms. One graduate student, one undergraduate student, and one postdoctoral researcher will be broadly trained in experimental physics and nanofabrication, and encouraged to present results at scientific meetings. By participating in this highly interdisciplinary research project, students will be well equipped for scientific careers. In addition, efforts to include women and minority researchers in the project will be undertaken.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.