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

使用激光冷却捕获微球测量微米级重力：延续提案

• 批准号: 1506431
• 负责人: Andrew Geraci
• 金额: $ 39.23万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506431&HistoricalAwards=false
• 关键词: Measuring; Gravity; Micron; Scale; Laser

Gravity is the least understood fundamental force of nature: there is a 16 order of magnitude disparity between the energy scale of quantum gravity and that of the electromagnetic and nuclear forces. The mystery can be cast in another way: why is gravity so much weaker? 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 our current knowledge. However, the gravitational force between massive objects becomes weak very rapidly as their size and separation distance changes, 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 test mass is suspended in a "container" made of light, leading to greatly reduced friction and enhanced sensitivity. This research program is at the forefront of current knowledge and will enhance the scientific competency of the state of Nevada, which is currently under-represented in terms of scientific endeavor. The collaboration with researchers at Stanford and the NSF-sponsored Stanford Nanofabrication facility will improve the research infrastructure for the state, opening new pathways for future collaborations involving nanotechnology. Students and postdoctoral researchers 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 work on an experiment with the goal of using 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 decoupling from the environment is possible, potentially yielding sub-attonewton force sensitivity. This new technique could ultimately advance our understanding of gravity at the micron length scale by a factor of 100,000 or more, probing deep into the parameter space for theoretically predicted deviations from Newtonian gravity. In addition to studies of short-range gravitational forces, the experimental technique we propose could also enable novel investigations of Casimir forces in unexplored regimes. The project is conceptually divided into three tasks: (1) calibration and optimization of the force sensitivity of the trapped cooled microspheres, (2) final assembly of the source mass and its driving mechanism, (3) investigation of systematic errors in preliminary gravity measurements. We will also investigate novel methods for cooling the levitated nanospheres, involving sympathetic cooling with cold atoms. A graduate physics course "Hybrid Quantum Systems" will be developed to complement and augment the proposed research, leading to new ideas and opportunities for advancing science, while developing students' breadth and expertise in STEM topics. This award is supported by the Gravitational Physics and the Atomic, Molecular and Optical Physics programs.

重力是自然的基本力量最少：量子重力的能量尺度与电磁和核力量之间存在16个数量级的差异。 这个谜可以以另一种方式施放：为什么重力如此弱？正如许多最近的理论所暗示的那样，可以通过测量在亚毫米距离处的重力行为来获得与此“层次结构问题”相关的重要线索。这样的测量可能会导致令人兴奋的物理学发现超出我们当前的知识。 但是，随着大小和分离距离的变化，大量物体之间的重力变得非常弱，从而使超敏感的测量在亚毫米长度尺度下是必需的。 该小组正在开发基于新技术的实验，该实验可以在微米长度上通过几个数量级来提高我们对重力的理解。在这种方法中，测试质量被悬挂在光线制成的“容器”中，从而大大降低了摩擦和增强的灵敏度。该研究计划处于当前知识的最前沿，并将增强内华达州的科学能力，而内华达州目前在科学努力方面的代表性不足。 与斯坦福大学的研究人员和NSF赞助的斯坦福大学纳米制作设施的合作将改善该州的研究基础设施，为涉及纳米技术的未来合作开辟了新的途径。 学生和博士后研究人员将接受实验物理和纳米制作的广泛培训，并将有效地进入科学劳动力。该项目的基本性质吸引了我们对自然世界的惊奇感。 该国将受益于以微观量表的一小部分与重力物理学相关的高能量物理学的了解，这是粒子挑战实验成本的一小部分。该奖项支持进行实验的工作，目的是使用激光冷却的小动物使用育川瓦（newton-Pepe）差异的纽顿（Newton-Pepe）偏差，以与新顿级的差异级别测试。通过光学悬浮的力传感器，可以从环境中进行精美的解耦，并可能产生亚音量的力敏感性。 这项新技术最终可以使我们在微米长度尺度上对重力的理解高达100,000倍以上，从而深入探测理论上预测与牛顿重力偏差的参数空间。 除了研究短距离引力力外，我们提出的实验技术还可以在未开发的方案中对Casimir力进行新的研究。 该项目在概念上分为三个任务：（1）校准和优化被捕获的冷却微球的力敏感性，（2）源质量及其驱动机制的最终组装，（3）研究初步重力测量中系统误差的研究。 我们还将研究用于冷却悬浮的纳米球的新型方法，涉及与冷原子的交感神经冷却。 将开发一个研究生物理课程“混合量子系统”，以补充和增强拟议的研究，从而为推进科学的新想法和机会，同时发展学生在STEM主题方面的广度和专业知识。该奖项得到了重力物理学和原子，分子和光学物理学计划的支持。