Measuring the electron electric dipole moment using an array of ultracold molecules

使用超冷分子阵列测量电子电偶极矩

基本信息

批准号：
ST/V00428X/1
负责人：
Jongseok Lim
金额：
$ 84.61万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FV00428X%2F1
关键词：
Measuring electron electric dipole moment

项目摘要

The Standard Model of particle physics is one of the greatest achievements of modern science. It has been fabulously successful in classifying the fundamental particles and explaining how they behave. Nevertheless, it is widely accepted that the Standard Model is incomplete because it fails to explain several important observations. One prominent example is the excess of matter over antimatter in the universe. The Standard Model predicts almost equal amounts of matter and antimatter, but observations show the universe contains only matter. This contradiction is one of the great unsolved problems in modern physics and a major deficiency of our most fundamental theory.To build a more complete picture of the universe, physicists are striving to reveal what lies beyond the Standard Model. This is an important objective of much of the research being done at gigantic particle accelerators. There is an alternative, and ingenious, way to explore the same problem - measure the shape of an electron. The new forces needed to explain the matter/antimatter imbalance also make electrons slightly non-spherical. This distortion - known as the electric dipole moment - changes the energy of an electron in an electric field, and that tiny change is amplified when the electron is bound to a molecule. I propose to build an apparatus that uses an array of molecules cooled to microkelvin temperatures to make an extremely precise measurement of the electron's shape. With very careful measurements, such table-top experiments enable us to probe energies equal to, or even above, those reached by the particle accelerators. Such marvellous precision has become possible by my recent success in cooling molecules to ultracold temperature. That technique is the foundation of this proposal.My plan is to decelerate a beam of ytterbium monofluoride molecules to rest using the forces exerted by carefully tuned laser light, trap these molecules and cool them to a few microkelvin. Then, I will load them into an array of traps formed by standing waves of light. The array contains millions of individual traps and isolates the molecules from one another, creating a pristine environment for measuring the electron's electric dipole moment. This measurement is done by watching how the spin of the molecules precesses in applied magnetic and electric fields, similar to the precession of a gyroscope or spinning top in a gravitational field. An electric dipole moment changes this precession rate, though only by the tiniest amount. That tiny change is detected more easily if the spin precesses for a long time. Because molecules are confined and isolated in the array, the time can be thousands of times longer than in current experiments. That makes my measurement scheme far more sensitive than any other experiment, allowing me to search for new physics with unprecedented precision.

粒子物理学的标准模型是现代科学的最大成就之一。它在对基本粒子进行分类并解释它们的行为方面取得了绝对的成功。然而，由于无法解释一些重要的观察结果，因此标准模型不完整是不完整的。一个突出的例子是宇宙中反物质的物质过剩。标准模型预测物质和反物质的数量几乎相等，但观察结果表明宇宙仅包含物质。这种矛盾是现代物理学中最重要的问题之一，也是我们最基本理论的主要缺陷。为了建立更完整的宇宙画面，物理学家正在努力揭示超出标准模型的内容。这是在巨大的粒子加速器上进行的许多研究的重要目标。有一种探索相同问题的替代方法，巧妙的方法 - 测量电子的形状。解释物质/反物质失衡所需的新力量也使电子略有非球面。这种失真 - 称为电偶极力矩 - 改变电场中电子的能量，当电子与分子结合时，微小的变化会放大。我建议构建一种使用冷却至微核动脉温度的分子阵列，以对电子形状进行非常精确的测量。通过非常仔细的测量，此类台式实验使我们能够探测粒子加速器所达到的能量，甚至更高。由于我最近在冷却分子到超低温度方面的成功，这种奇妙的精度已成为可能。该技术是该提案的基础。我的计划是使用仔细调节的激光灯施加的力，将Ytterbium单氟化物分子的束放在休息，将这些分子捕获并冷却到一些微胶菌。然后，我将它们加载到一系列由站立的光线形成的陷阱中。阵列包含数百万个单独的陷阱，并将分子彼此隔离，从而创建了原始的环境来测量电子的电偶极矩。通过观察分子在施加的磁场和电场中的旋转方式，类似于陀螺仪或引力场中旋转顶部的旋转。电动偶极力矩会改变此进动率，尽管仅通过最小的数量。如果旋转序列长时间，则更容易检测到这种微小的变化。由于分子在阵列中被限制和隔离，因此时间比当前实验的时间长几千倍。这使我的测量方案比任何其他实验都更加敏感，这使我可以以前所未有的精度搜索新物理学。