Error estimates of H^1-Galerkin mixed finite element method for Schrdinger equation

An H^1-Galerkin mixed finite element method is discussed for a class of second order SchrSdinger equation. Optimal error estimates of semidiscrete schemes are derived for problems in one space dimension. At the same time, optimal error estimates are derived for fully discrete schemes. And it is showed that the H1-Galerkin mixed finite element approximations have the same rate of convergence as in the classical mixed finite element methods without requiring the LBB consistency condition.

The Factorization Method to Solve a Class of Inverse Potential Scattering Problems for Schrdinger Equations

This paper is concerned with the inverse scattering problems for Schrdinger equations with compactly supported potentials.For purpose of reconstructing the support of the potential,we derive a factorization of the scattering amplitude operator A and prove that the ranges of （A＊ A） ^1/4 and G which maps more general incident fields than plane waves into the scattering amplitude coincide.As an application we characterize the support of the potential using only the spectral data of the operator A.

ON THE CONCENTRATION PROPERTIES FOR THE NONLINEAR SCHRDINGER EQUATION WITH A STARK POTENTIAL

In this paper, we study blow-up solutions of the Cauchy problem to the L2 critical nonlinear Schrdinger equation with a Stark potential. Using the variational characterization of the ground state for nonlinear Schrdinger equation without any potential, we obtain some concentration properties of blow-up solutions, including that the origin is the blow-up point of the radial blow-up solutions, the phenomenon of L2-concentration and rate of L2-concentration of blow-up solutions.

NODAL BOUND STATES WITH CLUSTERED SPIKES FOR NONLINEAR SCHRDINGER EQUATIONS

We consider the following nonlinear Schroodinger equations -ε^2△u ＋ u = Q（x）｜u｜^p-2u in R^N, u ∈ H^1（R^N）,where ε is a small positive parameter, N ≥ 2, 2 〈 p 〈 ∞ for N = 2 and 2 〈 p 〈2N/N-2 for N ≥ 3. We prove that this problem has sign-changing（nodal） semi-classical bound states with clustered spikes for sufficiently small ε under some additional conditions on Q（x）.Moreover, the number of this type of solutions will go to infinity as ε→ 0^＋.

Exact Radial Solution of the Non-relativistic Schrdinger Equation for the Helium Atom with the Potential Harmonic Method

We proposed a simple potential harmonic(PH) scheme for calculating the non\|relativistic radial correlation energies of atomic systems. The scheme was applied to the low\|lying \%n\%\+1\%S\%(\%n\%=1,2) and \%n\%\+3\%S\%(\%n\%=2,3) states of the helium atom. The results exhibit a very stable convergence characterization in both the angular and radial directions with PH and generalized Laguerre functions(GLF) respectively, even though the method is non\|variational one. The ninth significant figure of the non\|relativistic radial energy(NRE) calculated for the ground state exactly agrees with that of the most accurate literature data from the modified configuration interaction method. The convergent NRE′s for the excited states 2\+1\%S\%, 2\+3\%S\% and 3\+3\%S\% with the similar accuracy were also obtained.

Exact solitary wave solutions of a nonlinear Schrdinger equation model with saturable-like nonlinearities governing modulated waves in a discrete electrical lattice

In this paper, we introduce and propose exact and explicit analytical solutions to a novel model of the nonlinear Schr¨odinger(NLS) equation. This model is derived as the equation governing the dynamics of modulated cutoff waves in a discrete nonlinear electrical lattice. It is characterized by the addition of two terms that involve time derivatives to the classical equation. Through those terms, our model is also tantamount to a generalized NLS equation with saturable;which suggests that the discrete electrical transmission lines can potentially be used to experimentally investigate wave propagation in media that are modeled by such type of nonlinearity. We demonstrate that the new terms can enlarge considerably the forms of the solutions as compared to similar NLS-type equations. Sine–Gordon expansion-method is used to derive numerous kink, antikink, dark, and bright soliton solutions.

Nonautonomous solitary-wave solutions of the generalized nonautonomous cubic-quintic nonlinear Schrdinger equation with time-and space-modulated coefficients

A class of analytical solitary-wave solutions to the generalized nonautonomous cubic–quintic nonlinear Schrdinger equation with time-and space-modulated coefficients and potentials are constructed using the similarity transformation technique. Constraints for the dispersion coefficient, the cubic and quintic nonlinearities, the external potential, and the gain （loss） coefficient are presented at the same time. Various shapes of analytical solitary-wave solutions which have important applications of physical interest are studied in detail, such as the solutions in Feshbach resonance management with harmonic potentials, Faraday-type waves in the optical lattice potentials, and localized solutions supported by the Gaussian-shaped nonlinearity. The stability analysis of the solutions is discussed numerically.

Analytic Solutions of Klein-gordon Equation and Generalized Schrdinger Equation

Analytic solutions of Klein_gordon equat ionu tt -(u xx +u yy )+α 2u+g(uu *)u=0and generalized Schrdinger equationiu t+u xx -u yy +g(uu *)u=0are given when g(z)=Aln 2z+Blnz+C.

Attractors for Discrete Nonlinear Schrdinger Equation with Delay

In this paper,we first prove the existence of the global attractor Aν ∈ C（[-ν,0],2）（ν 0） for a weak damping discrete nonlinear Schrdinger equation with delay.Then we consider an upper semi-continuity of Aν as ν → 0＋.

A conservative local discontinuous Galerkin method for the solution of nonlinear Schrdinger equation in two dimensions

In this study, we present a conservative local discontinuous Galerkin(LDG) method for numerically solving the two-dimensional nonlinear Schrdinger(NLS) equation. The NLS equation is rewritten as a firstorder system and then we construct the LDG formulation with appropriate numerical flux. The mass and energy conserving laws for the semi-discrete formulation can be proved based on different choices of numerical fluxes such as the central, alternative and upwind-based flux. We will propose two kinds of time discretization methods for the semi-discrete formulation. One is based on Crank-Nicolson method and can be proved to preserve the discrete mass and energy conservation. The other one is Krylov implicit integration factor(IIF) method which demands much less computational effort. Various numerical experiments are presented to demonstrate the conservation law of mass and energy, the optimal rates of convergence, and the blow-up phenomenon.

Convergence of ground state solutions for nonlinear Schrdinger equations on graphs

We consider the nonlinear Schr¨odinger equation-?u +(λa(x) + 1)u = |u|^(p-1) u on a locally finite graph G =(V, E). We prove via the Nehari method that if a(x) satisfies certain assumptions, for any λ > 1, the equation admits a ground state solution uλ. Moreover, as λ→∞, the solution uλconverges to a solution of the Dirichlet problem-?u + u = |u|^(p-1) u which is defined on the potential well ?. We also provide a numerical experiment which solves the equation on a finite graph to illustrate our results.

A FINITE DIFFERENCE SCHEME FOR THE GENERALIZED NONLINEAR SCHRDINGER EQUATION WITH VARIABLE COEFFICIENTS

A finite difference scheme for the generalized nonlinear Schr dinger equation with variable coefficients is developed. The scheme is shown to satisfy two conservation laws. Numerical results show that the scheme is accurate and efficient.

Darboux Transformations, Higher-Order Rational Solitons and Rogue Wave Solutions for a(2+1)-Dimensional Nonlinear Schrdinger Equation

By Taylor expansion of Darboux matrix, a new generalized Darboux transformations(DTs) for a(2 + 1)-dimensional nonlinear Schrdinger(NLS) equation is derived, which can be reduced to two(1 + 1)-dimensional equation:a modified KdV equation and an NLS equation. With the help of symbolic computation, some higher-order rational solutions and rogue wave(RW) solutions are constructed by its(1, N-1)-fold DTs according to determinants. From the dynamic behavior of these rogue waves discussed under some selected parameters, we find that the RWs and solitons are demonstrated some interesting structures including the triangle, pentagon, heptagon profiles, etc. Furthermore, we find that the wave structure can be changed from the higher-order RWs into higher-order rational solitons by modulating the main free parameter. These results may give an explanation and prediction for the corresponding dynamical phenomena in some physically relevant systems.

A STRVCTURE-PRESERVING DISCRETIZATION OFNONLINEAR SCHRDINGER EQUATION

This paper studies the geometric structure of nonlinear Schrsdinger equationand from the view-point of preserving structure a kind of fully discrete schemes ispresented for the numerical simulation of this important equation in quantum. Ithas been shown by theoretical analysis and numerical experiments that such discrete schemes are quite satisfactory in keeping the desirable conservation propertiesand for simulating the long-time behaviour.

Compressible Limit of the Nonlinear Schrdinger Equation with Different-Degree Small Parameter Nonlinearities

The authors study the compressible limit of the nonlinear Schrdinger equation with different-degree small parameter nonlinearities in small time for initial data with Sobolev regularity before the formation of singularities in the limit system.On the one hand,the existence and uniqueness of the classical solution are proved for the dispersive perturbation of the quasi-linear symmetric system corresponding to the initial value problem of the above nonlinear Schrdinger equation.On the other hand,in the limit system,it is shown that the density converges to the solution of the compressible Euler equation and the validity of the WKB expansion is justified.

Spatiotemporal Self-Similar Solutions of the Generalized (3+1)-dimensional Nonlinear Schrdinger Equation with Polynomial Nonlinearity of Arbitrary Order

We construct analytical self-similar solutions for the generalized (3+1)-dimensional nonlinear Schrdinger equation with polynomial nonlinearity of arbitrary order. As an example, we list self-similar solutions of quintic nonlinear Schrdinger equation with distributed dispersion and distributed linear gain, including bright similariton solution, fractional and combined Jacobian elliptic function solutions. Moreover, we discuss self-similar evolutional dynamic behaviors of these solutions in the dispersion decreasing fiber and the periodic distributed amplification system.

Study of Exact Solutions to Cubic-Quintic Nonlinear Schrdinger Equation in Optical Soliton Communication

A systematic method which is based on the classical Lie group reduction is used to find the novel exact solution of the cubic-quintic nonlinear Schrdinger equation (CQNLS) with varying dispersion,nonlinearity,and gain or absorption.Algebraic solitary-wave as well as kink-type solutions in three kinds of optical fibers represented by coefficient varying CQNLS equations are studied in detail.Some new exact solutions of optical solitary wave with a simple analytic form in these models are presented.Appropriate solitary wave solutions are applied to discuss soliton propagation in optical fibres,and the amplification and compression of pulses in optical fibre amplifiers.

CONCENTRATION PHENOMENA TO THE NONLINEAR SCHRDINGER EQUATION WITH HARMONIC POTENTIAL IN GENERAL DATA

We analyze the blowup problems to the nonlinear Schrodinger equation with har-monic potential. This equation always models the Bose-Einstein condensation in lower dimensions. It is known that the mass of the blowup solutions from radially symmet-ric initial data can concentrate on the point of blowup. In this paper based on the refined compactness lemma, we extend the result to general data.

GLOBAL WEAK SOLUTION TO THE NONLINEAR SCHRDINGER EQUATIONS WITH DERIVATIVE

In this paper, we study the nonlinear Schr¨odinger equations with derivative. By using the Gal¨erkin method and a priori estimates, we obtain the global existence of the weak solution.

Singularly perturbed Neumann problem for fractional Schrdinger equations

This paper is concerned with a Neumann type problem for singularly perturbed fractional nonlinear Schrdinger equations with subcritical exponent. For some smooth bounded domain ? R^n, our boundary condition is given by∫_?u(x)-u(y)/|x-y|^(n+2s)dy = 0 for x ∈ R^n\?.We establish existence of non-negative small energy solutions, and also investigate the integrability of the solutions on Rn.