RESONANT INTERACTION BETWEEN A PAUL-TRAPPED ION AND A STANDING WAVE LASER

An ultracold two-level ion experiencing the standing wave of a resonant laser in a Paul trap is investigated in the Lamb-Dicke limit and weak excitation regime, with full consideration of the time-dependence of the trapping potential. The analytical forms of the wave functions of the system can be described with our approach, and the time evolution of the pseudo-energy of the system as well as the squeezing property of the quadrature components is studied in comparison with the treatment of harmonic oscillator model.     

量子Grover搜索在离子阱中的实现方案

本文在Cirac-Zoller模型的框架下,讨论在离子阱中如何实现多量子比特Grover搜索的方案。     

囚禁N2+离子的冷却实验

在Paul 阱中,开展了N2+离子电阻冷却和缓冲气体冷却实验。用抛出检测法精确测量离子信号的变化,提高了测量电阻冷却效果的灵敏度;用改变囚禁势的方法,测出了冷却离子的温度,观察到冷却离子的囚禁时间增加和速度分布范围减小的现象。     

Paul阱中基态低能多离化Fen+(n=1—3)离子的存储及反应特性

利用垂直交叉的激光束在Paul阱中溅射固体铸铁（FeC）靶，产生了低能多电荷铁离子 Feⁿ⁺(n=1—3), 得到了Fe³⁺离子在本底气压为3.0×10^-7 Pa下的衰减速率（0.96 s^-1）以及在1.3×10^-5 Pa下和中性气体分子N₂的反应产物. 关键词： Paul阱 低能多离化离子 反应特性     

Preliminary Frequency Comparison of Two 40^Ca^＋ Optical Frequency Standards

Frequency comparison is one of the most efficient ways to evaluate the performance of a frequency standard. Based on the pre-existing 40^Ca＋ optical frequency standard, we set up the second 40^Ca^＋ optical frequency standard, which has been improved in the materials and structure of ion traps for better control of the magnetic field. After the compensation, the residual magnetic field at the position of the ion is adjusted to be～500nT with a long time jitter of～10nT, which is better than the pre-existing 40^Ca^＋ optical frequency standard. We realize the ＇4-point-closed-loop locking＇ on the second 40^Ca＋ optical frequency standard after a series of preparatory works. Through half an hour of measurement time, the two frequency standards exhibited a stability of 2.1 × 10^-13.τ^1/2 and a relative frequency difference of 1.5 （2.9）Hz.     

Determining the structural phase transition point from the temperature of ~（40）Ca~＋ Coulomb crystal

We observed the linear-to-zigzag structural phase transition of a ^40Ca^＋ crystal in a homemade linear Paul trap. The values of the total temperature of the ion crystals during the phase transition are derived using the molecular-dynamics（MD） simulation method. A series of simulations revealed that the ratio of the radial to axial secular frequencies has a dependence on the total temperature that obeys different functional forms for linear and zigzag structures, and the transition point occurs where these functions intersect; thus, the critical value of the ratio of secular frequencies that drives the structure phase transition can be derived.     

离子光频标的原理和发展

人类对时间的计量历史可以追溯到几千年前,随着科学技术的发展与进步,人类对事件的计量精度也越来越精确。当前,世界上最精确的计时工具为光频标,可以达到百亿年不差一秒的水平。文章回顾了离子光频标的发展过程和当前的研究进展,简要介绍了钙离子光频标和量子逻辑铝离子光频标的原理及进展。     

Deceleration of Metastable Li~+ Beam by Combining Electrostatic Lens and Ion Trap Technique

Ion deceleration has played a critical role in ion-related research when the ions are produced in the form of a high-energy beam.We present a deceleration method combining electrostatic lens and ion trap technique,which can effectively decelerate ions to energy below the trapping potential of a typical ion trap.The experiments were performed on metastable 1s2s³S₁Li⁺ ions,and demonstrated that the kinetic energy could easily be reduced from ～450 e V to a few e V,w...     

金刚石簿膜淀积过程中微波等离子体特性

一、引言 在金刚石薄膜的制备过程中,人们往往监测成膜过程中的宏观参量,使其工艺的重复性,优选性受到了很大限制。而随着对膜质量和结构的要求越来越高,人们开始开展对低压下合成金刚石机理的研究,但至今未见系统地研究宏观参量与等离子体参量方面的工作报道。     

协变谐振子的介子结构模型的Kustannheimo-Stiefel变换求解

采用Kustannheimo-Stiefel变换(简称K-S变换),将四维协变谐振子的介子结构模型化为三维氢原子问题。在求解中能较自然地避开时间自由度激发的困难,求得介子质量谱的平方规律。 关键词：