Confinement of gaseous atoms with superfluid helium film and its application to the test of time-reversal symmetry

超流氦膜对气态原子的约束及其在时间反演对称性检验中的应用

• 批准号: 11304023
• 负责人: YABUZAKI Tsutomu
• 金额: $ 24.94万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11304023/
• 关键词: Gaseous alkali-metal atom; Optical pumping; Spin-polarization; Superfluid helium; Permanent electric dipole moment; Laser spectroscopy; High precision measurement; エキシマー

The purpose of this project is to realize the alkali vapor cell at liquid helium temperature, by coating the cell walls with superfluid helium film, suitable for the spin- related fundamental physics, particularly to the measurement of atomic electric dipole moment (EDM) for the test of time reversal symmetry. Through this project we could get various important results as follows.(1) We could realize experimentally alkali vapor cell, where the life of gaseous alkali atoms was as long as 10-100 s.(2) We could develop a novel method of production of alkali gaseous atoms, so called "light-induced atom desorption LIAD" method, witch can produce gaseous atoms with weak cw light, without strong convection.(3) It was found that the superfluidity of the liquid helium on the wall plays an important role for the LIAD, and the mechanism could be revealed.(4) Optical pumping experiment was made to the produced atoms in the cold cell. We found that the spin-relaxation time was determined by the lifetime of atoms 10-100 s.(5) We developed the method of atomic spin with the Faraday effect, which minimized the perturbation to the spin state. We also proposed the method of spin non-demolition measurement, which is very suitable for the atomic EDM measurement.(7) We also proposed and studied a novel method to observe the special distribution of spin polarization, optical magnetic-resonance imaging.(8) As a new effect of cold helium gas to alkali-metal atom, we found the formation of excimer and exciplexes, where helium atoms are sticking to the excited state alkali atoms. Trough spectroscopic studies of these excited-state molecules, we could determine their energies, including vibrational energies, and could get the information of formation.

本课题的目的是通过在细胞壁上包覆超流氦膜，实现在液氦温度下的碱蒸汽电池，该电池适用于自旋相关的基础物理，特别是原子电偶极矩（EDM）的测量，用于时间反转对称性的测试。通过这个项目，我们可以得到以下几点重要的结果。(1)可以通过实验实现碱蒸气池，其中气态碱原子的寿命长达10 ~ 100 s。(2)我们可以开发一种新的碱气体原子生成方法，即“光诱导原子解吸LIAD”方法，它可以在弱连续波光下产生气体原子，而不需要强对流。(3)发现液氦在壁面的超流动性对LIAD起重要作用，并揭示了其机理。(4)对冷阱中产生的原子进行光泵浦实验。我们发现自旋弛豫时间由原子的寿命10 ~ 100 s决定。(5)提出了利用法拉第效应进行原子自旋的方法，使自旋态的扰动最小化。我们还提出了一种适合于原子电火花加工测量的自旋不破坏测量方法。(7)提出并研究了一种观察自旋极化特殊分布的新方法——光学磁共振成像。(8)冷氦气对碱金属原子的新作用，发现了准分子和杂络合物的形成，其中氦原子粘附在激发态的碱金属原子上。通过对这些激发态分子的光谱研究，我们可以确定它们的能量，包括振动能量，并可以得到它们的形成信息。

项目成果

K. Ishikawa et al.: "Optical magnetic-resonance Imaging of laser-polarized Cs atoms"J. Opt. Soc. Am.. 16-1. 31-37 (1999)

K. Ishikawa 等：“激光偏振 Cs 原子的光学磁共振成像”J。

K.Ishikawa: "Diffusion coefficient and sublevel coherence of Rb atoms in N_2 baffer gas"Phys.Res.A. 62. 065401-1-4 (2001)

K.Ishikawa：“N_2缓冲气体中Rb原子的扩散系数和亚能级相干性”Phys.Res.A。

Y.Takahashi: "Observation of spin echoes of laser-cooled Rb atoms"Phys. Rev. A. 59-5. 3761-3765 (1999)

Y.Takahashi：“激光冷却 Rb 原子自旋回波的观察”Phys。

A. Hatakeyama: "Slow Spin Relaxation of Rb Atoms Confined in Glass Cells Filled with Dense 4He Gas at 1.85K"Phys. Rev. Lett.. 84. 1407-1410 (2000)

A. Hatakeyama：“限制在 1.85K 下充满致密 4He 气体的玻璃电池中的 Rb 原子的缓慢自旋弛豫”Phys。

K.Ishikawa: "Diffusion coefficient and sublevel coherence of Rb atoms in N2 buffer gas"Phys. Rev. A. 62. 065401-1-065401-4 (2000)

K.Ishikawa：“N2缓冲气体中Rb原子的扩散系数和亚能级相干性”Phys。