RUI: Search for a spin-gravity coupling using laser-addressed atomic gyroscopes

RUI：使用激光寻址原子陀螺仪寻找自旋重力耦合

• 批准号: 0652824
• 负责人: Derek Kimball
• 金额: $ 25.42万
• 依托单位: California State University, East Bay Foundation, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0652824&HistoricalAwards=false
• 关键词: RUI; Search; spin; gravity; coupling

This award supports an experiment to search for a new long-range coupling between nuclear spins and the mass of the Earth. Depending on interpretation, the experiment would improve present experimental limits by as much as two orders of magnitude or more. The presence of such an interaction would imply the existence of a gravitational dipole moment (GDM) of an elementary particle --- which can be envisioned semiclassically as a small separation between the position of the center of inertial mass and the center of gravitational mass. Detection of a GDM would be evidence that gravity violated parity and time-reversal symmetries to a small degree, as well as being a breakdown of the equivalence principle which underlies the theory of general relativity. The experiment would also set new experimental limits on hypothetical scalar and vector components of gravitational fields, and new limits on the existence of certain classes of massless or nearly massless axion-like pseudoscalar particles. This new experimental search is motivated by recently developed techniques in the field of atomic magnetometry enabling significant improvement in sensitivity to atomic spin precession. The experiment will use nonlinear optical rotation of near-resonant laser light to measure the spin-precession frequency of alkali atoms in the presence of a magnetic field and use differences between the frequencies for the two different ground state hyperfine levels to search for a signal proportional only to anomalous interactions.This work will fundamentally advance our knowledge of the gravitational force by testing how well gravity respects parity and time-reversal symmetries, and by probing the limits of the equivalence principle. Tremendous efforts at the theoretical level are being undertaken to integrate our understanding of gravity into the framework of quantum field theory, and this work offers a unique opportunity to gain new experimental insight into the symmetry properties of gravity. Furthermore, new techniques for precision measurement of the precession of spin-polarized atoms will be developed, advancing the technology driving the next generation of ultra-sensitive atomic magnetometers and gyroscopes.This research program forms the basis for an integrative approach to hands- on education in experimental physics at California State University, East Bay. New curricula for the advanced laboratory course will be developed to provide a natural connection to the ongoing research, and undergraduate students will be directly involved in the research program. An active research program at this institution will especially benefit a diverse student population, since two-thirds of our students are women and over seventy percent are underrepresented minorities.

该奖项支持一项寻找核自旋与地球质量之间新的远距离耦合的实验。根据不同的解释，这项实验将把目前的实验极限提高两个数量级或更多。这种相互作用的存在意味着一个基本粒子的引力偶极矩（GDM）的存在——这可以半经典地想象为惯性质量中心和引力质量中心之间的一个小的分离。探测到GDM将是引力在一定程度上违反宇称和时间反转对称性的证据，也是广义相对论基础上的等效原理被打破的证据。该实验还将对引力场的假想标量和矢量分量设定新的实验限制，并对某些类别的无质量或几乎无质量的类轴子伪标量粒子的存在设定新的限制。这项新的实验研究是由最近在原子磁强计领域发展起来的技术所推动的，这些技术能够显著提高对原子自旋进动的灵敏度。该实验将利用近共振激光的非线性光学旋转来测量在磁场存在下碱原子的自旋进动频率，并利用两个不同基态超精细能级的频率之差来寻找仅与异常相互作用成比例的信号。这项工作将从根本上提高我们对引力的认识，通过测试引力对宇称和时间反转对称性的尊重程度，并通过探索等效原理的极限。在理论层面上，人们正在进行巨大的努力，将我们对引力的理解整合到量子场论的框架中，这项工作为获得对引力对称性的新实验见解提供了一个独特的机会。此外，将开发用于精确测量自旋极化原子进动的新技术，推动下一代超灵敏原子磁强计和陀螺仪的技术发展。该研究项目为加州州立大学东湾分校实验物理实践教育的综合方法奠定了基础。高级实验课程的新课程将被开发，以提供与正在进行的研究自然联系，本科生将直接参与研究计划。这个机构积极的研究项目将特别有利于多样化的学生群体，因为我们三分之二的学生是女性，超过70%的学生是代表性不足的少数民族。