共查询到18条相似文献,搜索用时 125 毫秒
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通过对Paul阱中共线两Bi 形成的系统波函数、能谱和相对距离的平均值的精确计算,计算得到的频率、能量是目前的离子阱实验能达到的值;并且对共线两个Bi 的相对几率分布和系统能量本征态进行分析. 相似文献
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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Schrdinger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. 相似文献
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研究驻波型激光脉冲作用下,囚禁于Paul阱中的单离子在Lamb-Dicke区域的久期运动.通过试探解方法,得到系统的量子力学精确解.基于精确解描述的概率波包串,发现:1)波包串中心以及波包串的高度和宽度受激光脉冲强度的控制,通过调节激光强度可以控制波包串的形变和传播;2)在激光脉冲作用瞬间,离子的能量期待值发生跳变,而在激光关闭时段,有窄的能带形成;3)存在一个激光脉冲强度的临界值,在临界点附近,系统的稳定性发生变化.
关键词:
囚禁离子
激光脉冲
Lamb-Dicke近似
精确解 相似文献
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研究驻波型激光脉冲作用下,囚禁于Paul阱中的单离子在Lamb-Dicke区域的久期运动.通过试探解方法,得到系统的量子力学精确解.基于精确解描述的概率波包串,发现:1)波包串中心以及波包串的高度和宽度受激光脉冲强度的控制,通过调节激光强度可以控制波包串的形变和传播;2)在激光脉冲作用瞬间,离子的能量期待值发生跳变,而在激光关闭时段,有窄的能带形成;3)存在一个激光脉冲强度的临界值,在临界点附近,系统的稳定性发生变化. 相似文献
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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. 相似文献
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考虑赝势近似下囚禁于Paul阱中的单离子与双δ脉冲型周期势相互作用系统的规则与混沌运动.应用积分方程方法得到系统的经典运动精确解,通过数值方法作出相空间轨道图和平均能量的时间演化曲线.结合分析与数值结果,发现两个有趣的结论.即在离子与单δ脉冲作用出现共振失稳的情形,在双δ脉冲作用下却出现了稳定的规则运动;离子随着双δ脉冲中两个脉冲之间的时间间隔减小而由规则运动转为混沌运动,其平均能量扩散的快慢与混沌运动的混乱程度相关.还研究了系统的共振失稳,发现通过
关键词:
双δ脉冲
囚禁离子
精确解
混沌 相似文献
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Energy Eigenstates of a Quantum Gate System 总被引:3,自引:0,他引:3
Wenhua Hai Mang Feng Xiwen Zhu Lei Shi Kelin Gao Ximing Fang Min Yan 《International Journal of Theoretical Physics》2000,39(6):1405-1411
We report exact solutions of the Poyatos–Cirac–Zoller quantum gate system withtwo trapped ions [Phys. Rev. Lett.
81, 1322 (1998)]. It is the superposition ofentangled states among the pure states of two harmonic oscillators and describesa mixed mode involving the center-of-mass and relative motions withcommensurable frequencies. Theoretical analysis of the exact solutions showsthat for a given trapping frequency the relative motion cannot be laser-cooled. 相似文献
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In the present article, we consider the so‐called two‐spin equation that describes four‐level quantum systems. Recently, these systems attract attention due to their relation to the problem of quantum computation. We study general properties of the two‐spin equation and show that the problem for certain external backgrounds can be identified with the problem of one spin in an appropriate background. This allows one to generate a number of exact solutions for two‐spin equations on the basis of already known exact solutions of the one‐spin equation. Besides, we present some exact solutions for the two‐spin equation with an external background different for each spin but having the same direction. We study the eigenvalue problem for a time‐independent spin interaction and a time‐independent external background. A possible analogue of the Rabi problem for the two‐spin equation is defined. We present its exact solution and demonstrate the existence of magnetic resonances in two specific frequencies, one of them coinciding with the Rabi frequency, and the other depending on the rotating field magnitude. The resonance that corresponds to the second frequency is suppressed with respect to the first one. 相似文献
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Mario Cesar Baldiotti V. G. Bagrov D. M. Gitman A. D. Levin 《Brazilian Journal of Physics》2011,41(1):71-77
We describe some new exact solutions for two- and four-level systems. In all the cases, external fields have a restricted
behavior in time. First, we consider a method to construct new solutions for one-spin equation and give some explicit examples:
One of them is in a external magnetic field that acts during a finite time interval. Then we show how these solutions can
be used to solve the two-spin equation problem. A solution for two interacting spins is analyzed in the case when the field
difference between the external fields in each spin varies adiabatically, vanishing on the time infinity. The latter system
can be identified with a quantum gate realized by two coupled quantum dots. The probability of the Swap operation for such
a gate can be explicitly expressed in terms of special functions. Using the obtained expressions, we construct plots for the
Swap operation for some parameters of the external magnetic field and interaction function. 相似文献
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In the literature, there are numerous studies of one-dimensional discrete-time quantum walks (DTQWs) using a moving shift operator. However, there is no exact solution for the limiting probability distributions of DTQWs on cycles using a general coin or swapping shift operator. In this paper, we derive exact solutions for the limiting probability distribution of quantum walks using a general coin and swapping shift operator on cycles for the first time. Based on the exact solutions, we show how to generate symmetric quantum walks and determine the condition under which a symmetric quantum walk appears. Our results suggest that choosing various coin and initial state parameters can achieve a symmetric quantum walk. By defining a quantity to measure the variation of symmetry, deviation and mixing time of symmetric quantum walks are also investigated. 相似文献
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Xi-Zhou Qin 《Frontiers of Physics》2018,13(1):130302
We investigate the quantum dynamics of a driven two-level system under spontaneous emission and its application in clock frequency estimation. By using the Lindblad equation to describe the system, we analytically obtain its exact solutions, which show three different regimes: Rabi oscillation, damped oscillation, and overdamped decay. From the analytical solutions, we explore how the spontaneous emission affects the clock frequency estimation. We find that under a moderate spontaneous emission rate, the transition frequency can still be inferred from the Rabi oscillation. Our results enable potential practical applications in frequency measurement and quantum control under decoherence. 相似文献
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The problem of two-dimensional arbitrary amplitude low-frequency electrostatic oscillation in a quasi-neutral quantum plasma is solved exactly by elementary means. In such quantum plasmas we have treated electrons quantum mechanically and ions classically. The exact analytical solution of the nonlinear system exhibits the formation of dark and black solitons. Numerical simulation also predicts the possible periodic solution of the nonlinear system. Nonlinear analysis reveals that the system does have a bifurcation at a critical Mach number that depends on the angle of propagation of the wave. The small-amplitude limit leads to the formation of weakly nonlinear Kadomstev–Petviashvili solitons. 相似文献
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M. Mahdian M. Yahyavi R. Yousefjani 《International Journal of Theoretical Physics》2014,53(1):203-215
By starting from the stochastic Hamiltonian of the three correlated spins and modeling their frequency fluctuations as caused by dephasing noisy environments described by Ornstein-Uhlenbeck (OU) processes, we study the dynamics of quantum correlations, including entanglement and quantum discord. Of course, in this article, we use two definitions for the quantum discord (global quantum discord and quantum dissension). We prepared initially our open system with the Greenberger-Horne-Zeilinger (GHZ) and W states and present the exact solutions for evolution dynamics of entanglement and quantum discord between three spins under both Markovian and non-Markovian regime of this classical noise. By comparison the dynamics of entanglement with that of quantum discord we find that entanglement can be more robust than quantum discord against this noise. It is shown that by considering non-Markovian extensions the survival time of correlations prolong. Also, we compare the results of two definitions of the quantum discord and show that the quantum dissension is equal to the global quantum discord for GHZ state, but they are unequal for the W state. 相似文献
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O. Ciftja 《Physica B: Condensed Matter》2009,404(2):227-230
There has been a great deal of interest over the last two decades on the fractional quantum Hall effect, a novel quantum many-body liquid state of strongly correlated two-dimensional electronic systems in a strong perpendicular magnetic field. The most pronounced fractional quantum Hall states occur at odd denominator filling factors of the lowest Landau level and are described by the Laughlin wave function. It is well known that exact closed-form solutions for many-body wave functions, including the Laughlin wave function, are generally very rare and hard to obtain. In this work we present some exact results corresponding to small systems of electrons in the fractional quantum Hall regime at odd denominator filling factors. Use of Jacobi coordinates is the key tool that facilitates the exact calculation of various quantities. Expressions involving integrals over many variables are considerably simplified with the help of Jacobi coordinates allowing us to calculate exactly various quantities corresponding to systems with several electrons. 相似文献