空间分数阶Schr?dinger方程调制不稳定性的数值研究

调制不稳定性在数学和物理等学科中应用十分广泛.本文主要通过分裂谱方法对空间分数阶薛定谔方程进行数值计算,并根据Benjamin-Feir-Lighthill准则推导了非线性薛定谔方程的调制不稳定条件.文中分别研究了空间分数阶薛定谔方程在不同初值条件下的不稳定行为,并与整数阶薛定谔方程的不稳定性行为作比较,通过数值比较分析,发现整数阶薛定谔方程的这种不稳定行为对于空间分数阶薛定谔方程同样存在.     

一类相对非线性薛定谔方程解的存在性

利用临界点理论考虑了一类相对非线性薛定谔方程,主要通过变量代换将相对非线性薛定谔方程转化成半线性椭圆型方程.首先考虑位势函数为零时,将经典的场方程结果推广到了相对非线性薛定谔方程;而后利用临界点理论得到了有界位势情形方程非平凡解的存在性,在此情形,改进了文献[12-13]中的超线性条件.     

非齐次光纤介质中孤子解和奇异波的特性研究

以非齐次光纤介质中的非线性薛定谔方程为研究对象,采用相似变换将变系数非线性薛定谔方程转化为标准非线性薛定谔方程,然后利用待定系数法求出方程的孤子解和奇异波解.基于该解表达式,选取不同类型函数和相应参数进行数值模拟,分析其动力学特性,所得结果对研究孤子在非齐次光纤介质中的传播具有重要意义.     

非线性薛定谔方程的平均向量场方法

利用平均向量场方法(AVF)对非线性薛定谔方程进行求解, 在理论上得到了一个保非线性薛定谔方程描述的系统能量守恒的AVF格式, 再分别用非线性薛定谔方程的AVF格式和辛格式数值模拟孤立波的演化行为, 并比较两个格式是否保系统能量守恒特性. 数值结果表明, AVF格式也能很好地模拟孤立波的演化行为,并且比辛格式更能保持系统的能量守恒.     

高阶非线性薛定谔方程的精确解

通过修正的映射方法和推广的映射方法，我们得到了高阶非线性薛定谔方程新的精确解，它们是两个不同的雅可比椭圆函数的线性组合．并研究了在极限情况下高阶非线性薛定谔方程的解．     

薛定谔方程及薛定谔-麦克斯韦方程的多解

不作周期性和对称性的假设,也没有Ambrosetti-Rabinowitz增长控制条件,我们得到了一类超线性薛定谔方程在全空间中无穷多解的存在性结果.同时,得到了一类超线性薛定谔-麦克斯韦方程无穷多解的存在性结果.     

薛定谔方程在非一致网格下数值模拟的界面条件

本文研究了一维线性薛定谔方程在非一致网格下数值模拟的问题.在数值模拟中,非一致网格在界面处会产生虚假反射,利用局部时间步长和界面条件的方法,成功的减小了虚假反射.改进和提高了薛定谔方程数值模拟的效率和精度.     

变量分离法与变系数非线性薛定谔方程的求解探索

把变量分离法应用于(1+1) 维非线性物理模型，构建了色散缓变光纤变系数非线性薛定谔方程的一类新的孤子解.作为特例，也得到了常系数非线性薛定谔方程的包络型孤子解，只是解的形式有点变化.     

时空分数阶薛定谔方程的指数时间差分方法

本文针对时空分数阶非线性薛定谔方程,提出了应用Padé近似逼近Mittag-Leffler函数的指数时间差分格式,讨论了提高格式计算效率的方法.本文在具有各种参数的时空分数阶非线性薛定谔方程上进行了数值实验,实验结果说明了所提出方法的准确性、有效性和可靠性.     

薛定谔方程在非一致网格下数值模拟的界面条件（英文）

本文研究了一维线性薛定谔方程在非一致网格下数值模拟的问题.在数值模拟中,非一致网格在界面处会产生虚假反射,利用局部时间步长和界面条件的方法,成功的减小了虚假反射.改进和提高了薛定谔方程数值模拟的效率和精度.     

The original schröddinger wave equation revisited

We consider a nonlinear generalization of the Schrodinger wave equation in its original form and investigate its relationship with the corresponding time dependent Schrodinger equation     

Comment on “New types of exact solutions for nonlinear Schrodinger equation with cubic nonlinearity”

In this comment we analyze the paper [Abdelhalim Ebaid, S.M. Khaled, New types of exact solutions for nonlinear Schrodinger equation with cubic nonlinearity, J. Comput. Appl. Math. 235 (2011) 1984-1992]. Using the traveling wave, Ebaid and Khaled have found “new types of exact solutions for nonlinear Schrodinger equation with cubic nonlinearity”. We demonstrate that the authors studied the well-known nonlinear ordinary differential equation with the well-known general solution. We illustrate that Ebaid and Khaled have looked for some exact solution for the reduction of the nonlinear Schrodinger equation taking the general solution of the same equation into account.     

TIME DECAY FOR SCHR(O)DINGER EQUATION WITH ROUGH POTENTIALS

We obtain certain time decay and regularity estimates for 3D Schrodinger equation with a potential in the Kato class by using Besov spaces associated with Schrodinger operators.     

五次NLS方程全离散谱格式的大时间性态

Nonlinear Schroedinger equation arises in many physical problems. There are many works in which properties of the solution are studied. In this paper we use fully discrete Fourier spectral method to get an approximation solution of nonlinear weakly dissipative Schroedinger equation with quintic term. We give a large-time error estimate and obtain the existence of the approximate attractor A N^k.     

Numerical solution of the nonlinear Schrodinger equation by feedforward neural networks

We present a method to solve boundary value problems using artificial neural networks (ANN). A trial solution of the differential equation is written as a feed-forward neural network containing adjustable parameters (the weights and biases). From the differential equation and its boundary conditions we prepare the energy function which is used in the back-propagation method with momentum term to update the network parameters. We improved energy function of ANN which is derived from Schrodinger equation and the boundary conditions. With this improvement of energy function we can use unsupervised training method in the ANN for solving the equation. Unsupervised training aims to minimize a non-negative energy function. We used the ANN method to solve Schrodinger equation for few quantum systems. Eigenfunctions and energy eigenvalues are calculated. Our numerical results are in agreement with their corresponding analytical solution and show the efficiency of ANN method for solving eigenvalue problems.     

On Properties of Solutions of the Cauchy Problem for the Schrodinger Equation Degenerate on the Half-Line

We consider the Schrodinger equation on the half-line describing a particle with mass depending on its location. We study the Cauchy problem for the Schrodinger equation with degenerate operator whose characteristic form vanishes on the half-line. A sequence of regularizing Cauchy problems with uniformly elliptic operators is considered, and the convergence of the sequence of solutions of nondegenerate problems to the solution of the degenerate problem is examined.__________Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 10, Suzdal Conference-4, 2003.     

A geometric characterization of the nonlinear Schrodinger equation and its applications

We prove that the nonlinear Schrodinger equation of attractive type (NLS+ describes just spher-ical surfaces (SS) and the nonlinear Schrodinger equation of repulsive type (NLS-) determines only pseudo-spherical surfaces (PSS). This implies that, though we show that given two differential PSS (resp. SS) equationsthere exists a local gauge transformation (despite of changing the independent variables or not) which trans-forms a solution of one into any solution of the other, it is impossible to have such a gauge transformationbetween the NLS+ and the NLS-.     

New analysis and application of fractional order Schrödinger equation using with Atangana–Batogna numerical scheme

In this work, an analytical approximation to the solution of Schrodinger equation has been provided. The fractional derivative used in this equation is the Caputo derivative. The existence and uniqueness conditions of solutions for the proposed model are derived based on the power law. While solving the fractional order Schrodinger equation, Atangana–Batogna numerical method is presented for fractional order equation. We obtain an efficient recurrence relation for solving these kinds of equations. To illustrate the usefulness of the numerical scheme, the numerical simulations are presented. The results show that the numerical scheme is very effective and simple.     

Boundary Value Problems for the Stationary Schrodinger Equation on Riemannian Manifolds

We suggest a new approach to the statement of boundary value problems for elliptic partial differential equations on arbitrary Riemannian manifolds which is based on the consideration of equivalence classes of functions on a manifold. Using this approach, we establish some interrelation between the solvability of boundary value problems and solvability of exterior boundary problems for the stationary Schrodinger equation. Also we prove the comparison and uniqueness theorems for solutions to boundary value problems in this statement and obtain sufficient conditions for solvability of boundary value problems when the coefficient in the Schrodinger equation is changed.     

再论弹性大挠度问题von Kármán方程与量子本征值问题Schrǒdinger方程的关系

本文是文[1]的继续和改善。利用本文的结果,还可以改善文[2～3]中有关弹性大挠度问题的讨论。在本文中,我们再次对弹性大挠度问题的von Kármán方程进行简化,使它最终成为非线性Schr?dinger方程。其次,在本文中我们对AKNS方程在多维条件下进行了更为对称的拓展。由于非线性Schr?dinger方程与AKNS方程即Dirac方程的可积性条件相联系,因此,弹性大挠度问题可以用逆散射方法求得其精确解,也就是说,它完全成了量子本征值问题。对于正交各向异性大挠度问题,本文也作了推论。