Non-Newtonian Forces

现代物理学的一个主要目标是尽可能在最基本的水平上理解物质和能量的性质和行为，这些物质和能量是我们宇宙的基本组成部分。爱因斯坦弱场(牛顿)引力的经验测试在判断这种理解的可能扩展方面发挥了重要作用，这种理解体现在所谓的基本相互作用标准模型中。即使与牛顿行为的微小偏差也可能构成违反目前所制定的标准模型的证据。偏差尚未被发现，但在过去十年的理论文献中，预计这种异常在低水平上的可能性比比皆是。该项目的目标是实施一项实验，该实验将通过对假定的非牛顿相互作用的强度设定至少比现在建立的更严格的数量级上限来显著限制这些推测的可行性。或者，这些更精确的测量可能会发现以前没有检测到的偏差。与加州大学欧文分校的一个团队合作，利用低温技术在测量精度方面取得了新的进展，开发了显著减少系统影响的方法，并建立了一个新的实验室设施，提供了一个超低振动环境，允许利用这些实质性的改进。该仪器只有一个移动部件，一个由细丝悬挂的精确配置的石英质量块。最先进的光电技术被用来以极高的灵敏度监测这个质量块绕灯丝轴的旋转。正是在精心控制的条件下，没有这样的自转，才构成了牛顿行为的实验表现--即使是最小的运动也表明了违规(这是新物理学的可能证据)。因此，这项测试的灵敏度取决于能够可靠地检测到多小的旋转角。为了说明该项目的测量能力，这一最小可检测到的自转角度相当于从华盛顿州中心俯瞰华盛顿纪念碑顶部人类头发的宽度。所有这些活动都涉及年轻科学家--博士后、研究生和本科生--以及企业合作伙伴巴特尔实验室、波音飞机公司和机构赞助商太平洋西北国家实验室，所有这些都参与了尽可能广泛地扩大研究和教育推广的努力。

A primary goal of modern physics is to understand at the most fundamental level possible the nature and behavior of matter and energy, the basic components of our universe. Empirical tests of Einstein's weak-field (Newtonian) gravity play an important role in judging possible extensions of this understanding, embodied in the so-called Standard Model of fundamental interactions. Even small deviations from Newtonian behavior could constitute evidence for violation of the Standard Model as currently formulated. Deviations have not yet been found, but the possibilities for expecting such anomalies at a low level abound in the theoretical literature over the past decade. The goal of this project is to bring to operation an experiment that will substantially restrict the viability of these speculations by setting at least an order-of-magnitude more stringent upper limit on the strength of putative non-Newtonian interactions than now established. Alternatively, these more precise measurements could uncover previously undetected deviations. Either outcome would advance fundamental understanding of matter and energy.In collaboration with a group at UC Irvine, new advances in measurement precision using cryogenic techniques have been exploited, methods to dramatically reduce systematic effects have been developed, and a new laboratory facility that provides an ultra-low vibration environment that allows exploitation of these substantial improvements has been established. The instrumentation has only a single moving part, a precisely configured quartz mass suspended by a thin filament. State-of-the-art electro-optic technology is used to monitor the rotation of this mass about the filament axis with extreme sensitivity. It is the absence of such a rotation, under carefully controlled conditions, that constitutes the experimental manifestation of Newtonian behavior -- violation (and possible evidence for new physics) is indicated by even the smallest movement. Hence, the sensitivity of this test depends on how small a rotation angle can reliably be detected. To provide an illustration of the project's measurement capability, this minimum detectable rotation is comparable to the angle subtended by the width of a human hair located at the top of the Washington Monument as viewed from the center of the State of Washington.All these activities involve young scientists -- post-docs, graduate and undergraduate students -- as well as corporate partners Battelle Laboratories, Boeing Airplane Co. and institutional sponsor Pacific Northwest National Laboratory, all involved in efforts to extend the quality of the research and educational outreach as broadly as possible.