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Renewal of “Understanding Gravity at the Smallest Scale”

更新“理解最小尺度的重力”

基本信息

批准号：
2108244
负责人：
Giorgio Gratta
金额：
$ 48万
依托单位：
Stanford University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-15 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108244&HistoricalAwards=false
关键词：
Renewal Understanding Gravity Smallest Scale

项目摘要

Understanding the nature of gravity at microscopic distances is one of the most important open problems in fundamental physics. Although General Relativity provides an extremely well-tested framework for describing gravitational effects at large distances, its connection with quantum mechanics and other fundamental interactions remains elusive. Indeed, the development of a quantum theory of gravity that can be incorporated into the Standard Model of fundamental interactions is a central goal of physics, with broad implications for our understanding of particle physics and the mysterious nature of the "dark energy" that appears to permeate the universe. Many theories attempting to provide a consistent microscopic framework for gravity (e.g., those involving extra dimensions) predict that gravity could deviate from the familiar inverse square law at sub-millimeter distances. Such deviations are extremely difficult to measure experimentally due to the small strength of gravitation and the presence of residual electromagnetic interactions. This grant funds the continuation of an experimental program in this area that has just started providing results.Previous measurements at these distance scales have employed techniques derived from human-size devices in which mechanical springs are used as part of force sensors. In the last few years, with the support of the NSF, the PI has developed a drastically new technique, using the light field of a laser to confine and measure the motion of micron-size quartz microspheres. In the last year the first full search for deviations from the inverse square law in the 10 micron range has been completed. While not yet competitive with the most sensitive measurements, this represents the first demonstration of the new technique that more directly measures forces at the range of interest, instead of extrapolating with objects that are larger than such range. In addition to this, the systematics are expected to be very different from those of other measurements and there are indications that background force models will soon be within reach. Additionally, the new technique used has been found to have many other applications in other areas of fundamental as well as applied physics. In the first category are searches for millicharged particles or tests of neutrality of matter, while inertial navigation and vacuum technology are examples of the second.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.

在微观距离上理解引力的本质是基础物理学中最重要的开放性问题之一。虽然广义相对论为描述远距离引力效应提供了一个非常好的框架，但它与量子力学和其他基本相互作用的联系仍然难以捉摸。事实上，发展一种可以纳入基本相互作用标准模型的量子引力理论是物理学的一个中心目标，对我们理解粒子物理学和似乎渗透宇宙的"暗能量"的神秘性质具有广泛的影响。许多理论试图为引力提供一个一致的微观框架（例如，那些涉及额外维度的理论）预测，在亚毫米的距离上，重力可能偏离熟悉的平方反比定律。由于引力的强度很小，并且存在残余的电磁相互作用，这种偏差很难通过实验测量。该基金资助了这一领域的一个实验项目的继续，该项目刚刚开始提供结果。以前在这些距离尺度上的测量采用了来自人体大小的设备的技术，其中机械弹簧被用作力传感器的一部分。在过去的几年里，在NSF的支持下，PI开发了一种全新的技术，使用激光的光场来限制和测量微米级石英微球的运动。在过去的一年中，第一次全面搜索偏离平方反比定律在10微米范围内已经完成。虽然与最敏感的测量相比还没有竞争力，但这代表了新技术的首次演示，该技术更直接地测量感兴趣范围内的力，而不是用大于该范围的物体进行外推。除此之外，预计这些系统将与其他测量结果大不相同，有迹象表明，背景力模型将很快实现。此外，所使用的新技术已被发现在基础物理和应用物理的其他领域有许多其他应用。第一类是寻找毫荷电粒子或物质中性测试，第二类是惯性导航和真空技术。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。