Precision Tests of Contemporary Ideas in Gravitational/Particle Physics

该奖项支持华盛顿大学Eot-Wash小组开发新颖，高灵敏度的扭转平衡仪器，以寻找现代理论物理思想所允许的超弱力；特别是试图将引力与其他三种基本力统一起来。这种统一面临着两个深刻的问题：与其他已知的力相比，引力极其微弱；宇宙常数与真空能量密度的量子力学预测之间存在巨大的差异。克服这些问题的理论思想经常预测新的引力现象，这些现象可以用改进的仪器进行测试。特别是，(1)牛顿的平方反比定律将被测试到比人类头发直径小得多的长度尺度，以探测“大”的额外维度，并测试对观测到的宇宙常数小的可能解释。这些测试应该能够探测到长度小至25微米的新的引力强度相互作用；(2)爱因斯坦的弱等效原理将以比以前发表的结果高50倍的灵敏度进行测试。这将测试爱因斯坦相对论引力理论的一个关键假设，并将填补正在进行的强等效原理月球激光测距测试中的一个漏洞。它还探索了关于神秘的“暗能量”来源的猜测，暗能量似乎占宇宙总质量能量的三分之二；(3)一个包含近1摩尔极化电子的特殊扭转摆将用于几个前所未有的灵敏度的新实验，包括寻找冻结在宇宙中的违反cpt的场，寻找宏观的违反cp的相互作用，寻找宏观的，速度依赖的，违反p的相互作用，以及寻找由当前关于“幽灵凝聚”引力的想法预测的奇异自旋-自旋相互作用；(4)新的扭平衡仪器将投入使用，用于寻找类轴子粒子产生的力。Eot-Wash小组应用实验万有引力技术来解决万有引力、基本粒子和宇宙学社区感兴趣的各种基本问题。这项研究要求并产生了技术创新，这些创新已经在其他领域得到了应用，比如引力波探测。该小组的研究成果通过出版物和座谈会、特邀演讲、实验室参观和公开讲座广泛传播，并在该国和欧洲的杂志和报纸上刊登。Eot-Wash小组解决的各种科学问题和涉及的许多实验挑战为研究生和博士后提供了良好的实验物理教育，同时也为本科生的研究项目提供了非常有吸引力的机会。该奖项将为研究生、博士后研究人员和几个本科项目提供支持。

This award supports the University of Washington Eot-Wash Group to develop novel, highly-sensitive torsion-balance instruments to search for the ultra-weak forces allowed by modern ideas in theoretical physics; especially attempts to unify gravity with the other three fundamental forces. This unification is faced with two deep problems: the extreme weakness of gravity compared to the other known forces, and the enormous observed disparity between the cosmological constant and the quantum-mechanical predictions of the vacuum-energy density. Theoretical ideas for overcoming these problems often predict new gravitational phenomena that can be tested with improved instruments. In particular, (1) Newton's inverse-square law will be tested down to length scales substantially smaller than the diameter of a human hair to probe for "large" extra dimensions and to test a possible explanation for the observed smallness of the cosmological constant. These tests should be able to probe new gravitational-strength interactions with length scales down to 25 micrometers; (2) Einstein's Weak Equivalence Principle will be tested with a sensitivity 50 times better than previously published results. This will test a key postulate of Einstein's relativistic theory of gravity and will close a loophole in the ongoing Lunar-Laser-Ranging test of the Strong Equivalence Principle. It also probes speculations about the source of the mysterious "dark energy" that appears to comprise two thirds of the total mass-energy of the Universe; (3) A special torsion pendulum containing almost a mole of polarized electrons will be used for several novel experiments of unprecedented sensitivity including a search for CPT-violating fields frozen into the universe, a search for macroscopic CP-violating interactions, a search for macroscopic, velocity-dependent, P-violating interactions, and a search for the exotic spin-spin interactions predicted by current ideas about "ghost condensate" gravity; (4) A new torsion-balance instrument will be commissioned and used to search for the force produced by axion-like particles.The Eot-Wash Group has applied the techniques of experimental gravitation to address a broad variety of basic questions of interest to the gravitational, elementary-particle and cosmology communities. This research has required and produced technical innovations that have found applications in other areas such as gravity-wave detection. The Group's results are widely disseminated through publications and by colloquia, invited talks, lab tours and public lectures, and have been featured in magazine and newspaper articles in this country and in Europe. The variety of scientific issues addressed by the Eot-Wash Group and the many experimental challenges involved provide an excellent education in experimental physics for graduate students and postdoctoral fellows, as well as unusually attractive opportunities for undergraduate research projects. This award will provide support for graduate students, postdoctoral researchers and several undergraduate projects.