共查询到20条相似文献,搜索用时 15 毫秒
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Solitons and Breathers of Electromagnetic Wave in Superlattices 总被引:4,自引:0,他引:4
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A New Approach to Solve Nonlinear Wave Equations 总被引:3,自引:0,他引:3
From the nonlinear sine-Gordon equation, new transformations are obtained in this paper, which are applied to propose a new approach to construct exact periodic solutions to nonlinear wave equations. It is shown that more new periodic solutions can be obtained by this new approach, and more shock wave solutions or solitary wave solutions can be got under their limit conditions. 相似文献
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对平面电磁波入射到横向分层不均匀介质上时的情形,麦克斯韦方程组可简化成马丢(Mathieu)方程和希尔(Hil)方程,据此可获得透射波和反射波场的解析表达式。从所获得的解我们得知,介质的非均匀性可改变入射波的强度分布和偏振状态,这种改变取决于多种因素,比如介质非均匀的具体形式,入射波的入射和偏振方向等;反射波的强度分布可被也可不被改变,取决于波和介质的参数 相似文献
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Two-Level Atom in a Standing, Electromagnetic Wave 总被引:2,自引:0,他引:2
Su Kalin Luo Wenhua Xu Xiao Yang Keqi 《International Journal of Theoretical Physics》2003,42(7):1641-1650
We study a two-level atom interacting with a standing electromagnetic wave, and work out the wave functions, the energy values and the momentum values of the atom. 相似文献
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ZENGGao-Jian 《理论物理通讯》2001,35(1):83-86
We study behavior of an atomic wave packet in a circularly polarized electromagnetic wave,and particularly calculate the atomic inversion of the wave packet.A general method of calculation is presented.The results are interesting.For example,if the wave packet is very narrow or /and the interaction is very strong,no matter the atom is initially in its ground state or excited state,the atomic inversion approaches zero as time approaches infinity.If the atom is initially in its ground state and excited state with the probability 1/2 respectively,and if the momentum density is an even function,then the atomic inversion equals zero at any time. 相似文献
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M. B. Belonenko S. Yu. Glazov N. E. Meshcheryakova 《Journal of Russian Laser Research》2008,29(2):114-122
We considered the Maxwell equations for electromagnetic-field propagation in a solid with a one-dimensional semiconductor
superlattice of quantum dots in the case where the spectral width of the electromagnetic pulse is sufficient to excite transitions
between different minizones. A phenomenological equation was obtained in the form of the classical one-dimensional sine-Gordon
equation with the perturbation caused by quantum transitions between the minizones. Quantum behavior of electrons was considered
using the microscopic Hamiltonian, in the assumption that the pulse duration is small enough for the phonon effects to be
neglected. The equation obtained was analyzed numerically, and cases where the adiabatic perturbation theory for the sine-Gordon
equation can be used were found. Numerical solutions were obtained, and the domain where transitions between the minizones
play a significant role in the electromagnetic-pulse dynamics was found.
Talk presented at the oral issue of J. Russ. Laser Res. dedicated to the memory of Professor Vladimir A. Isakov, Professor
Alexander S. Shumovsky, and Professor Andrei V. Vinogradov held in Moscow February 21–22, 2008. 相似文献
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We study a two-level atom interacting with an electromagnetic wave of circle polarization, and work out the wave functions,
the energy values and momentum values of the atom.
PACS: 32.80.-t, 03.65.Ge 相似文献
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TUTao CHENGGeng 《理论物理通讯》2003,40(4):390-392
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A theoretical study of Bloch electron transport in a superlattice miniband driven by an electric field parallel to the growth axis is carried out, by Fokker-Planck equation (FPE) in momentum space with the averaged momentum relaxation time (γ) approximation. Steadystate drift-velocity/field characteristics exhibit the expected maximum followed by negative differential conductivity (NDC), and then followed by drift-velocity oscillation when γ or electric field is large. The oscillation frequency is an increasing function of γ, and when γ → ∞, the limit of the oscillation frequency is the Bloch frequency as expected. 相似文献
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A (3+1)-dimensional Gross-Pitaevskii (GP) equation with time variable coefficients is considered, and is transformed into a standard nonlinear Schrodinger (NLS) equation. Exact solutions of the (3+1)D GP equation are constructed via those of the NLS equation. By applying specific time-modulated nonlinearities, dispersions, and potentials, the dynamics of the solutions can be controlled. Solitary and periodic wave solutions with snaking and breathing behavior are reported. 相似文献
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Solitons of the sine-Gordon system interacting with a disturbed external field are handled by using a direct method. Theoretical analysis reveals that the single soliton perturbed by a periodic field leads to chaotic behavior of the system, and the perturbed double soliton is unstable for most of physically interesting spacetime disturbances. 相似文献
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We construct analytical periodic wave and soliton solutions to the generalized nonautonomous nonlinear Schrödinger equation with time- and space-dependent distributed coefficients in harmonic and optical lattice potentials. We utilize the similarity transformation technique to obtain these solutions. Constraints for the dispersion coefficient, the nonlinearity, and the gain (loss) coefficient are presented at the same time. Various shapes of periodic wave and soliton solutions are studied analytically and physically. Stability analysis of the solutions is discussed numerically. 相似文献
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对VHF/UHF波段电磁波传播模型和人工神经网络算法特性进行了分析,认为可以根据大量的实测数据,利用人工神经网络算法,建立起适合于本地使用的电磁波传播模型.该算法符合现代理念的"数据驱动"思想,所建立的模型具有强非线性特点,有较好的可修正性,很好地解决了模型本地化问题. 相似文献
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Ziqiang Yang Haiyuan Chen Zheng Liang 《International Journal of Infrared and Millimeter Waves》2002,23(7):1057-1064
The frequency spectrum of free-electron laser pumped by electromagnetic wave with magnetized and unmagnetized background plasma is analyzed by the theory of three-wave interaction and PIC simulation, respectively. The frequencies of PIC simulation are in agreement with the results of the three-wave interaction theory. The results show that the frequency spectrum is very plentiful. 相似文献
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DAI Chao-Qing ZHANG Jie-Fang 《理论物理通讯》2006,46(7)
In this paper, we generalize the extended tanh-function approach, which was used to find new exact travelling wave solutions of nonlinear partial differential equations or coupled nonlinear partial differential equations, to nonlinear differential-difference equations. As illustration, two series of exact travelling wave solutions of the discrete sine-Gordon equation are obtained by means of the extended tanh-function approach. 相似文献