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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.

在微观距离下理解重力的本质是基础物理学中最重要的开放性问题之一。尽管广义相对论为描述远距离引力效应提供了一个经过充分验证的框架，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，量子引力理论的发展可以被纳入基本相互作用的标准模型，这是物理学的一个中心目标，对我们理解粒子物理学和似乎弥漫在宇宙中的“暗能量”的神秘本质具有广泛的意义。许多试图为引力提供一致的微观框架的理论（例如，那些涉及额外维度的理论）预测，引力可能在亚毫米距离上偏离熟悉的平方反比定律。由于引力强度小，并且存在残余的电磁相互作用，这种偏差在实验上很难测量。这项奖助金用于在该领域继续进行一项刚刚开始取得成果的实验计划。以前在这些距离尺度上的测量采用了源自人体大小的设备的技术，其中机械弹簧用作力传感器的一部分。在过去的几年里，在国家科学基金会的支持下，PI开发了一种全新的技术，利用激光的光场来限制和测量微米尺寸的石英微球的运动。去年，在10微米范围内对平方反比定律偏差的首次全面研究已经完成。虽然还不能与最灵敏的测量相媲美，但这代表了新技术的第一次演示，该技术更直接地测量感兴趣范围内的力，而不是外推大于该范围的物体。除此之外，预计系统分析结果将与其他测量结果大不相同，而且有迹象表明，背景力模型将很快实现。此外，已经发现所使用的新技术在基础物理学和应用物理学的其他领域有许多其他应用。第一类是对带电粒子的搜索或对物质中性的测试，而惯性导航和真空技术是第二类的例子。该奖项反映了美国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。