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量子力学中的散射问题一直是学习的难点,也是理论研究的基础.本文是为了理解散射提供一个精确可解的例子.我们获得了一维定态薛定谔方程在th(λx)势下的精确解,并在精确解的基础上,利用超几何函数的渐近展开性质,计算出相应的反射系数和透射系数.同时还发现当常数λ趋于无穷大极限时,th(λx)势与阶梯势对应的反射系数和透射系数正好相等. 相似文献
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利用分离变量法得到了2+1维Nizhnik-Novikov-Veselov方程包含三个任意函数的精确解.合 适地选择任意函数,该精确解可以是描述所有方向指数局域的dromion相互作用,三个方向 指数局域的‘Solitoff’和dromion相互作用以及线孤子和y周期孤子相互作用的解.对dromi on相互作用从解析和几何两个角度进行了详细地探讨,揭示了一些新的相互作用规律.
关键词:
dromions相互作用
NNV方程
分离变量法 相似文献
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基于微分方程多边形的概念,就一些直接代数方法给出了几何解释,同时将这种解释推广到方程组的情形,最后以变形Boussinesq方程组为例说明了该几何解释的合理性。
关键词:
微分方程
多边形
几何解释
精确解 相似文献
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基于等几何分析方法具有自由度花费少、高精度、高阶连续性等特点,通过加权余量法对椭圆波导本征问题的亥姆霍兹方程等几何离散得出等几何分析方程.解决了传统数值方法的求解域与几何模型的非一致性问题,实现了将问题的分析计算构架于精确几何模型基础之上.分析任意截面波导的本征问题,对不同偏心率的椭圆波导以及三角形和五边形波导的截止波数的求解结果显示等几何分析方法求解波导本征问题的高效及高精度特性.与传统方法相比,此方法以较少的自由度消耗便会达到较高的求解精度,并且数值解的收敛率较快. 相似文献
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为了获得非线性发展方程新的无穷序列复合型精确解,给出了Riccati方程的Bäcklund变换和解的非线性叠加公式,符号计算系统Mathematica的帮助下,以广义Boussinesq方程为应用实例,获得了无穷序列复合型精确解.这里包括双曲函数、三角函数与有理函数复合解、双曲函数与三角函数复合解等几种新的无穷序列复合型精确解.该方法在构造非线性发展方程无穷序列复合型精确解方面具有普遍意义.
关键词:
非线性发展方程
非线性叠加公式
Riccati方程
无穷序列精确解 相似文献
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BERRY PHASES IN THE QUANTUM STATE OF THE ISOTROPIC HARMONIC OSCILLATOR WITH TIME-DEPENDENT FREQUENCY AND BOUNDARY CONDITIONS
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The problem of the isotopic harmonic oscillator of time-dependent frequency confined in a spherical box with time-dependent radius is studied. We show that the exact solution and the Lewis invariant operator can be obtained by performing two consecutive gauge transformations on the time-dependent Schr?dinger equation. On the basis of the exact solution the non-adiabatic Berry phases for the system are calculated. 相似文献
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使用代数方法给出了粒子质量显含时间的Dirac方程的严格解,解的结构显示了粒子的正负能态与其自旋态具有交换对称性.
关键词: 相似文献
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利用量子不变量理论研究了任意随时间变化的强磁场中碱金属原子系统的演化问题,得到了此系统精确的演化态,并利用此精确的演化态求出了相应的Anaronov-Anandan相因子和绝热极限下的Berry相因子。将此系统精确的演化态按哈密顿量的瞬时本征态展开,可以得到绝热近似的任意阶修正。 相似文献
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A. A. Suzko 《Physics of Particles and Nuclei Letters》2007,4(2):143-145
A method of constructing periodic time-dependent Hamiltonians admitting exact solutions is used to study the geometric phase.
The approach is based on the transformation of soluble time-independent equations into time-dependent ones by employing a
set of special time-dependent transformation operators. A class of periodic time-dependent Hamiltonians with cyclic solutions
is constructed in a closed analytic form and the nonadiabatic geometric phase is determined in terms of the obtained solutions.
The text was submitted by the author in English. 相似文献
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In connection with Bitter-Dubbers experiment, an exact solution for the quantum dynamics of neutrons in magnetic field which is harmonically inhomogeneous (helical) and changes harmonically with time is obtained by invoking a time-dependent transformation with spin space coupling. It predicts that a beam of neutrons with monotonous momentum will be split into two beams by the magnetic field. As its limiting case, the Berry's geometric phase in moving reference frame appears while the field is very strong. 相似文献
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The Lewis'invariant and exact solution for the driven generalized time-dependent harmonic oscillator is found by making use of the Lewis-Riesenfeld quantum theory. Then, the adiabatic asymptotic limit of the exact solution is discussed and the Berry's phase for thirr system is obtained. We then proceed to use the exact solution to construct the coherent state and calculate the corresponding exact classical phase angle. This phase angle can give the Hannay's angle in the adiabatic limit. The relation between the exact Lewis'phase and the corresponding classical phase angle L'discusrred. 相似文献
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We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependent rotating magnetic field. Based on the
algebraic structure of the non-autonomous system, the exact solution of the Schrödinger equation is obtained by using the method of algebraic dynamics. Based on the time-dependent analytical solution, we further study the entanglement evolution between the two coupled spins for different initial states, and find that the entanglement is determined by the coefficients of the initial state and the coupling constant $J$ of the system. 相似文献
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我们研究了含时旋转磁场中海森堡XXX模型下的双量子比特的动力学演化情况.基于此非自治系统的代数结构,我们用代数动力学方法求得了系统的精确解析解.在此基础上,进一步研究了在不同初态下系统的纠缠测度随时间的演化,发现纠缠测度由系统的初态的系数和耦合强度决定. 相似文献