Probing Fundamental Physics with Gravitational Experiments

在现代物理学中，用两种理论来描述自然。一个是“标准模型”，它用量子粒子描述所有物质的性质；另一个是“广义相对论”，爱因斯坦的理论，它描述了万有引力。大多数物理学家认为这两个理论之间肯定有联系，但到目前为止，还没有实验签名来证明这种联系。此外，暗物质和暗能量的发现表明，引力现象存在于广义相对论之外。华盛顿大学的这个小组专门测量超微弱的力量，以寻找广义相对论所描述的前所未有的微小引力偏差。尽管观测到与广义相对论的任何偏离都将是一项革命性的科学发现，但它也可能对GPS或下一代精密时钟的未来技术应用产生影响。此外，使用为重力测量开发的仪器，该小组将寻找暗物质的特征。该小组开发的技术和技术专长的应用范围从工业计量学到地震预测，再到准备该国的STEM劳动力。将引力和粒子物理以及暗能量和暗物质观测相结合的现代想法表明，引力的某些方面仍未被发现。华盛顿大学重力实验室(Eöt-Wash Group)的桌面实验提供了一个独特的机会，可以在广义相对论、宇宙学和粒子物理学的交叉点上寻找新的物理。该小组通过技术专长和创新，并通过回应最相关、及时和永恒的物理问题，在fi领域是超弱力探测领域的领导者。具体地说，该小组将：1)测试等价原则(EP)：几乎可以肯定的是，广义相对论和标准模型之间的任何联系都违反了EP。该集团的扭力天平提供了最精确的实验室EP测试。通过熔融石英扭转光纤、新的重力梯度测量、改进的钟摆和更好的仪器控制，将进行新的EP测量，其在约束B-L联轴器方面的灵敏度将比集团以前的测量高达15倍。此外，通过探测涉及富氢测试质量的EP，将增强EP测试的一般性和与宇宙学的相关性。2)短距离测试牛顿平方反比定律(ISL)：该小组将利用其在短距离测量重力方面的专业知识建造一台新仪器，并进行测量以测试短至20微米的距离的重力。3)使用扭转天平搜索超轻暗物质。4)推进低频超小力技术前沿：创新和具有挑战性的技术发展使集团取得了成功。该小组将进一步改进角度测量，并开发干涉和电容式测距仪。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In modern physics nature is described by two theories. One is the “Standard Model,” which describes all material properties with quantum particles; the other is “General Relativity”, Einstein’s theory that describes gravitation. Most physicists think that there must be a connection between these two theories, but to date there is no experimental signature for such a connection. Furthermore, the discoveries of dark matter and dark energy suggest that gravitational phenomena exist that lie outside of General Relativity. The group at the University of Washington specializes in measuring ultra-feeble forces to search for unprecedentedly small deviations from gravity as described by General Relativity. While observing any deviations from General Relativity would be a revolutionary scientific discovery, it may also have consequences for future technical applications of GPS or next-generation precision clocks. Furthermore, using instruments developed for gravity measurement, the group will look for signatures of dark matter. Technology and technical expertise developed by this group has applications ranging from industrial metrology to earthquake prediction to preparing the country’s STEM workforce.Modern ideas for unifying gravity and particle physics, as well as the observation of dark energy and dark matter, suggest that some aspects of gravity remain undiscovered. The table-top experiments of the University of Washington gravity laboratory (Eöt-Wash Group) provide a unique opportunity to search for new physics at the intersection of General Relativity, cosmology, and particle physics. The group is a leader in the field of ultra-weak force detection through technical expertise and innovation and by responding to the most relevant timely and timeless physics questions. Specifically, the group will: 1) Test the equivalence principle (EP): It is almost certain that any connection between General Relativity and the Standard Model violates the EP. The group’s torsion balances provided the most precise laboratory EP-tests. With highly increased sensitivity through fused silica torsion fibers, a novel gravity gradient measurement, an improved pendulum and better instrument control, new EP measurements will be carried out that will be up to 15 times more sensitive than the group’s previous measurements in constraining B-L couplings. Furthermore, the EP-test’s generality and relevance to cosmology will be enhanced by probing the EP involving hydrogen-rich test masses. 2) Test Newton's Inverse-Square Law (ISL) at short distances: The group will use its expertise in measuring gravity at short distances to build a new instrument and carry out measurements to test gravity at distances as short as 20 µm. 3) Search for ultra-light dark matter using torsion balances. 4) Advance the frontier of low-frequency ultra-small-force technology: Innovative and challenging technology development has enabled the group’s success. The group will further improve angle measurement and develop interferometric and capacitive distance gauges.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.