Precision measurements with polarized spins

极化旋转的精确测量

• 批准号: 0801042
• 负责人: Ronald Walsworth
• 金额: $ 36万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0801042&HistoricalAwards=false
• 关键词: Precision; measurements; polarized; spins

This research program is aimed at performing three precision experimental searches for new physics beyond the standard model of particle physics. The experiments use a maser operating simultaneously with Xe-129 and He-3. By stabilizing one of the noble-gas masers to a frequency reference, the PI's group can control the environment of the masers and then use the other maser as a sensor for new physics. The experiments to be carried out include: (i) a sensitive test of the fundamental Lorentz invariance (one of the fundamental aspects of the theory of relativity) and CPT (Charge conjugation, Parity, and Time reversal) symmetry for the neutron; (ii) an order-of-magnitude improved search for the effects of torsion gravity, which arises if spacetime has a Riemann-Cartan geometry; and (iii) a sensitive search for anomalous spin-spin interactions in the neutron sector. For experiment (i) and (ii) the project is expected to provide an order-of-magnitude improvement compared to the best previous limits. Much of our understanding of fundamental physics would have to be radically altered if an effect is observed. Experiment (iii) will provide a first sensitive search of this effect.Broader impacts of the program include the application of the atomic physics based precision measurement techniques of this research into the development of novel biomedical imaging tools (for example magnetic resonance imaging (MRI) at low magnetic fields of hyperpolarized noble gas inhaled into human lungs), as well as the development of a high-sensitivity magnetometer using nitrogen vacancy centers in diamond. Other broader impacts include extensive student training with continued successful focus on inclusion and training in precision measurements techniques of students and postdocs who are members of underrepresented groups in science and engineering.

这项研究计划的目的是在粒子物理标准模型之外进行三次精确的实验搜索，以寻找新的物理学。实验使用的微波激射器与Xe-129和He-3同时工作。通过将其中一个惰性气体脉泽稳定在一个参考频率上，PI的团队可以控制脉泽的环境，然后将另一个脉泽用作新物理的传感器。将要进行的实验包括：(i)对中子的基本洛伦兹不变性（相对论的一个基本方面）和CPT（电荷共轭、奇偶性和时间反转）对称性进行敏感测试；（ii）如果时空具有黎曼-卡尔坦几何，那么对扭转引力效应的研究将得到数量级上的改进；（iii）对中子扇区中异常自旋-自旋相互作用的灵敏搜索。对于实验(i)和（ii），预计该项目将比以前的最佳限制提供一个数量级的改进。如果观察到这种效应，我们对基础物理学的大部分理解将不得不从根本上改变。实验（iii）将提供对这种效应的第一次敏感搜索。该计划的更广泛影响包括将原子物理学的精密测量技术应用于新型生物医学成像工具的开发（例如，在吸入人体肺部的超极化惰性气体的低磁场下进行磁共振成像（MRI）），以及利用金刚石中的氮空位中心开发高灵敏度磁强计。其他更广泛的影响包括广泛的学生培训，继续成功地关注科学和工程领域代表性不足的学生和博士后的精密测量技术的包容和培训。