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对定向凝固界面前沿非稳态溶质扩散场进行了系统的对比分析,发现无论在纯扩散还是存在对流的情况下,界面前沿的溶质扩散场通常满足指数分布的形式,可以采用一个统一的公式来描述界面前沿的瞬态溶质扩散场.进而在此基础上,对定向凝固界面形态稳定性进行了统一的时间相关的非稳态分析,发现界面临界稳定性条件的数学描述形式与Mullins和Seker ka理论给出的稳态解完全一致, 只是用时间相关的浓度梯度GtC、界面速度Vi、溶质扩散长度l代替了稳态生长中所得到的GC,V,DL/V. 相似文献
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Analytical Solution for Single—Mode Time—Dependent Oscillator 总被引:1,自引:0,他引:1
Based on the general theory of time-dependent quantum transformation,we use the “time evolution operator” method to solve the single-mode time-dependent oscillator. 相似文献
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We study the dynamics of classical and quantum particles moving in a punctured plane under the influence of a homogeneous magnetic field and driven by a time-dependent singular flux tube through the hole. 相似文献
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Berry phase of coupled two arbitrary spins in a time-varying magnetic field 总被引:2,自引:0,他引:2 下载免费PDF全文
In this paper, we investigate the Berry phase of two coupled arbitrary spins
driven by a time-varying magnetic field where the Hamiltonian is explicitly
time-dependent. Using a technique of time-dependent gauge transform the
Berry phase and time-evolution operator are found explicitly in the
adiabatic approximation. The general solutions for arbitrary spins are
applied to the spin-1/2\ system as an example of explanation. 相似文献
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We use the separation of variable treatment to treat some time-dependent systems,and point out that the condition of separability is the same as the condition of existence of invariant,and the separation of variable treatment is interrelated with the quantum-invariant method and the propagator method.We directly use the separation of variable treatment to obtain the wavefunctions of the time-dependent Coulomb potential and the time-dependent Hulthen potential. 相似文献
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含时耦合谐振子体系的动力学演化 总被引:1,自引:0,他引:1
利用含时量子变换理论,给出含时双模耦合谐振子的严格解.并根据这一结果,对于给定的初态为Fock态和相干态情形,讨论了其动力学演化. 相似文献
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In this paper, the Non-Commutative phase space and Dirac equation, time-dependent Dirac oscillator are introduced. After presenting the desire general form of a two-dimensional linear dependency on the coordinate time-dependent potential, the Dirac equation is written in terms of Non-Commutative phase space parameters and solved in a general form by using Lewis-Riesenfield invariant method and the time-dependent invariant of Dirac equation with two-dimensional linear dependency on the coordinate time-dependent potential in Non-Commutative phase space has been constructed, then such latter operations are done for time-dependent Dirac oscillator. In order to solve the differential equation of wave function time evolution for Dirac equation and time-dependent Dirac oscillator which are partial differential equation some appropriate ordinary physical problems have been studied and at the end the interesting result has been achieved. 相似文献
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本文从理论角度提出了一种"含时贝塞尔光束"的概念.在非傍轴和非时谐条件下,直接从麦克斯韦方程出发,借鉴半贝塞尔光束的处理方法,同时引入第四维虚数坐标,由此获得了完整的"含时贝塞尔光束"的解析表达式.并从无衍射性质和时空特性两个方面对其进行了探讨和研究,发现该光束具有如下性质:符合贝塞尔光束类型的无衍射特征;在时空双曲线上强度保持不变;光波时空特性的临界条件类似于相对论中的光锥."含时贝塞尔光束"的概念为无衍射自加速光束的研究开拓了新的思路和方向. 相似文献
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含时阻尼线性谐振子的量子不变量处理 总被引:1,自引:0,他引:1
在适当的正则化变换下,采用Lewis-Riesenfeld量子不变量理论,得到了含时阻尼线性谐振子的精确波函数,波函数的正确性和普遍性同样得到讨论. 相似文献
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The Berry phase in a composite system induced by the time-dependent interaction is discussed. We choose two coupled spin-1/2 systems as the composite system: one of the subsystems is subjected to a static magnetic field, and the coupling parameters between two spins are controllable in time. We show that the time-dependent interaction can induce the Berry phase in a similar way as that a spin-1/2 system (qubit) is driven by an effective time-dependent magnetic field. Furthermore, using two consecutive cycles with opposite directions of both the static magnetic field as well as opposite signs of the coupling parameters, a nontrivial two-qubit unitary transformation purely based on Berry phases can be constructed. 相似文献
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ZHANG Xiao-Fei ZHANG Pei YANG Qin 《理论物理通讯》2008,50(12):1323-1326
We obtain the integrable relation for the one-dimensional nonlinear Schrodinger equations which describes the dynamics of a Bos-Einstein Condensates with time-dependent scattering length in a harmonic potential. The exact one- and two-soliton solutions are constructed analytically by using the Hirota method. Then we further discuss the dynamics of the one soliton and the interactions between two solitons in currently experimental conditions. 相似文献
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We propose a variant of the time-dependent multi-configuration Hartree method within the framework of Fourier grid Hamiltonian
method. The workability of the method proposed is demonstrated with a well-known coupled two-mode problem. 相似文献
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The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the
classical equation of motion. In terms of this dynamical invariant we define the time-dependent creation and annihilation operators and relevantly introduce even and odd coherent states
for time-dependent harmonic oscillator. The mathematical and quantum statistical properties of these states are discussed in detail. The harmonic oscillator with periodically varying frequency is treated as a
demonstration of our general approach. 相似文献
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The scaling properties of higher cumulants for a diffusion problem are examined by means of numerical calculations. The exponent for the higher cumulants are found to be less than that of the first cumulant but larger than that of the second one. The calculations can be used for describing quantum particle diffusion in a random time-dependent potential, domain wall diffusion in a 2D magnet, etc. 相似文献