Tests of the gravitational inverse square law and equivalence principle, and cryogenic torsion pendulum development

引力平方反比定律和等效原理的测试以及低温扭摆的开发

• 批准号: 0404514
• 负责人: Riley Newman
• 金额: $ 80.1万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0404514&HistoricalAwards=false
• 关键词: Tests; gravitational; inverse; square; law

A program of laboratory tests of fundamental gravitational physics laws is to be extended, in parallel with development of the cryogenic torsion pendulum as a general tool for research in gravitational physics. Included in the research program are: 1) a test of the inverse square distance dependence of the gravitational force for mass separation on the order of 15 centimeters, 2) tests of the weak equivalence principle over various ranges, for gravitational field sources which include laboratory masses, a nearby mountain, and the sun, and 3) completion of a measurement of the gravitational constant G. These projects are conducted in a remote underground laboratory (Battelle Gravitational Physics Laboratory, BGPL) which has been prepared with support from the Pacific Northwest National Laboratory in a former Nike missile bunker on an isolated environmental preserve near Richland, Washington. Most of this work is done in collaboration with the gravitational physics group of Paul Boynton at the University of Washington.A discovery of deviation of the apparent gravitational force from the inverse square distance dependence of Newton's law of gravity could signal the existence of new fundamental forces in Nature, with profound implications for the laws of physics. Similarly, discovery of a violation of the weak equivalence principle which asserts that all objects fall with the same acceleration in a gravitational field, would have profound implications. This principle, which is a foundation stone of Einstein's theory of General Relativity, is predicted by many modern theories of gravitation to fail at some level. The measurement of the gravitational constant G will help resolve significant discrepancies among a number of measurements of this fundamental constants made in the last two decades. Technological development of the cryogenic torsion pendulum used in this work will be of potential benefit to a wide range of experimental research in which it is important to measure small macroscopic forces with extreme sensitivity.

在发展低温扭转摆作为引力物理研究的通用工具的同时，还将扩展一个基本引力物理定律的实验室测试计划。研究计划包括：1)对质量分离的引力的平方距离倒数关系进行15厘米量级的测试；2)对包括实验室质量、附近的山脉和太阳在内的引力场来源在不同范围内进行弱等效原理测试；3)完成对引力常数G的测量。这些项目是在一个偏远的地下实验室(巴特尔引力物理实验室，BGPL)进行的，该实验室是在太平洋西北国家实验室的支持下准备的，位于华盛顿州里奇兰附近一个孤立的环境保护区上的一个前耐克导弹掩体中。这项工作的大部分是与华盛顿大学保罗·博因顿的引力物理学小组合作完成的。如果发现表观引力偏离牛顿引力定律的平方距离倒数关系，可能表明自然界存在新的基本力，这将对物理定律产生深远的影响。同样，发现对弱等价原理的违反，即所有物体在引力场中以相同的加速度下落，将产生深远的影响。这一原理是爱因斯坦广义相对论的基石，许多现代引力理论都预测它在某种程度上会失败。引力常数G的测量将有助于解决过去二十年来对这一基本常数的许多测量之间的重大差异。这项工作中使用的低温扭转摆的技术发展将对广泛的实验研究有潜在的好处，在这些实验研究中，以极高的灵敏度测量微小的宏观力是很重要的。