Effect of the Double Frequency of Trap Field in a Paul Trap

The effect of double frequency oftrap field φ = U - V1 cos Ωt - V2 cos 2Ωt in a Paul trap can be described exactly by using a function series expansion to solve the corresponding Mathieu equation.The stability regions of a trapped ion are plotted and some meaningful physical results are shown.``     

Detail Study of the Resonant Transition in a Paul Trap

The resonant transition in the Paul trap is studied by the time-space transformation and function series expansion. A new selection rule for the transition in the trap is derived strictly. Tlte probability in the ground state and solrle transition rates to the excited states are calculated. Tlte comparison with the former studies shotvs that our results are more accurate and credible.     

Paul 阱中共面三离子的量子力学问题

对Paul阱中共面三离子体系作了研究,通过分析其总角动量L=2时的情形单体密度和形状密度,确定了体系的结构和内部运动情况,并与总角动量L=0和经典情形进行了比较。     

Axial resonances of Ar + ions observed in a linear Paul trap

Non-neutral plasmas composed of 10⁶ to 10⁷ Ar⁺ ions were confined in a linear Paul trap which had a non-harmonic electrostatic potential in axial direction. Axial resonances were observed by applying additional RF electric field and detecting axially ejected ions. It was found that the resonance frequencies shifted as a function of the ion number, the amplitude of additional RF electric field, and the applied electrostatic potential for the axial confinement.      

Coherence-Like States of Two Coulomb-Correlated Ions Confined in a Paul Trap

We report the n x n＇ coherence-like state solutions in the cases of n, n＇ = 1, 2,... for the system including two Coulomb-correlated ions confined in a one-dimensional Paul trap with a time-dependent harmonic potential. One of the n＇ exact solutions of the centre-of-mass motion describes a generalized coherent state. For a small driving strength the n approximate solutions of relative motion are constructed, which describe the coherent oscillations of the two ions around the classical equilibrium position.     

Calculation of the Storage Time of the Ions Confined in a Paul Trap

A Brownian motion model for the energy of the ions trapped in the pseudopotential well of a Paul trap is proposed and the exact solutions of the storage time in terms of the mean first passage time (MFPT) in the cases of white noises and colored noises are theoretically calculated. The relationships with the damping coefficient, noise parameters and the energy distribution of the ions are also discussed.     

Paul阱中一维两离子系统的能带结构

利用熟知的级数截断方法，设计数值程序计算了线形Paul阱中库仑关联的两离子系统Schrdinger方程的精确解，得到接近目前离子阱实验能够实现的阱频下系统分立的运动态波函数和能谱，它们对应于阱频值的一个无穷可数的点集.在该点集内两相邻点之间连续变化阱频，由量子微扰法得到以精确分立谱为基础的能带结构，包括较宽的能隙和较窄的带宽.能带结构的存在将影响以该系统为基础的量子逻辑操作和激光边带冷却等问题，应该在实验研究中加以考虑.     

Solitary waves in a long structure of charged particles confined in the linear Paul trap

This paper demonstrates the possibility of generation of density waves in the form of individual humps in a long structure of the one-component Coulomb system of dust particles confined in the linear Paul traps in air under normal conditions Our numerical simulations by particle-in-cell method support this possibility. Physical possibility of analogous the hump density waves (caustics) is discussed by V.I. Arnold in his book ‘Catastrophe Theory’ and is caused by the nonuniform velocity distribution of dust particles.     

Experimental investigation of the stability diagram for Paul traps in the case of praseodymium ions

The present paper describes an investigation of non-linear resonances of praseodymium ion clouds stored in a Paul trap as a function of the storage parameters. These have been observed in traps with different ring electrode diameters. In these different traps the resonances occur for different values of the operating parameters. Discrepancies with the approximation model for one ion have been found. The intensity of the fluorescence signal and the Doppler half width have been recorded as a function of one of the storage parameters: q. We use our results to optimize the fluorescence signal of the stored ions, which is especially useful in the case of the double-resonance method.     

Laser Controlling Wavepacket Trains of a Paul Trapped Ion

We have studied the quantum and classical motions of a single Paul trapped ion interacting with a time-periodic laser field. By using the test-function method, we construct n exact solutions of quantum dynamics that describe the generalized squeezed coherent states with the expectation orbits being the corresponding classical ones. The space-time evolutions of the exact probability densities show some wavepacket trains. It is demonstrated analytically that by adjusting the laser intensity and frequency, we can control the center motions of the wavepacket trains. We also discuss the other physical properties such as the expectation value of energy, the widths and heights of the wavepackets, and the resonance loss of stability.     

Paul阱中囚禁的低能Ar2+离子与Ar的电荷转移

在Paul阱中产生并选择囚禁了单一的Ar2 离子,得到低能Ar2 与Ar的电荷转移速率系数为5.84(0.677)×10-10cm3·s-1及其零氩气压强下的离子衰减速率为0.46 s-1,为下一步进行多电荷离子的亚稳态寿命研究提供了有价值的实验参考数据.     

Paul阱中存储离子的研究

根据Paul离子阱结构及电场分布特点,列出阱内离子运动方程并求解,对其中离子运动、硅团簇离子碰撞解离反应进行了分析.     

Paul阱中离子运动及稳定性分析

Paul离子阱由于没有外加磁场所引起的塞曼效应的影响,已成为离子存储及研究离子的重要装置.根据在实验中所采用的Paul离子阱结构及电场分布特点,列出阱内离子运动方程并进行求解,对其中各种运动进行分析,同时还分析了离子存储稳定性.最后对所作的研究进行总结,得到如下结论:阱中离子的运动为谐振运动、基频微运动和高阶微振动.     

非谐射频阱中离子云系统的精确周期解

射频阱中离子云与检测场的相互作用由周期驱动的Duffing方程描述.本文报道了该方程的一个精确的周期解,它描述了阱参数和外场对离子云周期运动的影响.结果表明,在各参变量满足周期解条件时,离子的运动频率为外场频率的三分之一,运动振幅分别与外场频率、振幅以及阱频正相关,与离子阱的非谐参数反相关.     

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     

Laser controlled quantum motion of two Paul trapped ions

We investigate the quantum motion of two ions stored in a Paul trap and interacting with a time-periodic laser field. In the pseudopotential approximation and large detuning condition, we find that the relative motion is independent of the laser field, but the exact centre-of-mass motion is closely related to the laser field. By adjusting the laser intensity and frequency, we can well control the quantum motion of the centre-of-mass. We illustrate some physical properties described by the centre-of-mass states, such as the squeezed coherent property, the widths and heights of the wavepackets of probability density, the classical-quantum correspondence, the resonance ladders of expectation energy and the transition probabilities between time-dependent quantum levels.     

高斯噪声诱导二元混合物/粒子系统有序结构的形成

采用蒙特卡罗方法研究高斯噪声场对添加硬球粒子的二元混合物系统自组装的驱动作用.发现硬球粒子与组分之间的相互作用决定硬球粒子在畴中存在的区域.当硬球粒子与组分之间的相互作用较大,硬球粒子浓度n≤0.05时,对于足够强的高斯噪声场,存在一个最佳噪声作用概率区域(p=0.005~0.02),其间高斯噪声已完全消除硬球粒子的钉扎效应,使体系快速生长并形成取向性很好的条状畴结构.     

Paul阱内的压缩效应与量子跃迁

处理一个一维Ｐａｕｌ阱系统中的压缩现象与量子跃迁现象，对于阱内的最强压缩态和共振跃迁（一种极不稳定状态）之间的关系作了阐述，并对利用压缩性质在阱内进行精密测量的可能性作了讨论     

Detection of Isotopes of Mercury Ions by Resonant Ejection in Paul Trap

A simple method to detect mercury ions confined in a Paul trap has been developed by resonant ejection. In this method, frequency of the additional ejection ac voltage is scanned instead of the amplitude of the rf drive voltage in conventional methods. It is possible not only to observe the spectra of the secular oscillation of the trapped ions directly, but also to eject the confined ions from the trap mass-selectively.     

Fluorescence Detection and Buffer Gas Cooling of Trapped Mercury Ions in Paul Trap

Pig ions are confined in a hyperboloid ion trap. With the rf discharge ^202 Hg isotope lamp, the fluorescence signal of trapped Hg ions is observed. By means of buffer gas cooling, the ionic temperature is reduced. As a result, the trapping time is increased and the signal-to-noise ratio （SNR） of the fluorescent signal is improved. The temperature of ion cloud is estimated by measuring the space charge shift.