Existence and concentration of solutions for Schrödinger–Poisson system with steep potential well

This paper is concerned with the nonlinear Schrödinger–Poisson system where λ > 0 is a parameter. We require that V≥0 and has a bounded potential well V^?1(0). Combining this with other suitable assumptions on K and f, the existence of nontrivial solutions is obtained by using variational methods. Moreover, the concentration of solutions is also explored on the set V^?1(0) as λ→∞. Copyright © 2015 John Wiley & Sons, Ltd.     

Positive ground states for asymptotically periodic Schrödinger–Poisson systems

In this paper, we establish the existence of positive ground states for asymptotically periodic Schrödinger–Poisson systems with general nonlinearities by the method of Nehari manifold. Copyright © 2012 John Wiley & Sons, Ltd.     

Existence of ground state solutions for asymptotically linear Schrödinger–Poisson systems

In this paper, we study the following Schrödinger–Poisson system: where λ > 0 is a parameter, with 2≤p≤+∞, and the function f(x,s) may not be superlinear in s near zero and is asymptotically linear with respect to s at infinity. Under certain assumptions on V, K, and f, we give the existence and nonexistence results via variational methods. More precisely, when p∈[2,+∞), we obtain that system (SP) has a positive ground state solution for λ small; when p =+ ∞, we prove that system (SP) has a positive solution for λ small and has no any nontrivial solution for λ large. Copyright © 2015 John Wiley & Sons, Ltd.     

Positive ground state solutions for a class of Schrödinger–Poisson systems with sign‐changing and vanishing potential

This paper deals with the following Schrödinger–Poisson systems where λ, ν are positive parameters and V(x) is sign‐changing and may vanish at infinity. Under some suitable assumptions, the existence of positive ground state solutions is obtained by using variational methods. Our main results unify and improve the recent ones in the literatures. Copyright © 2016 John Wiley & Sons, Ltd.     

Positive solutions for asymptotically linear Schrödinger–Kirchhoff‐type equations

In this paper, we focus on the Schrödinger–Kirchhoff‐type equation (SK) where a,b > 0 are constants, may not be radially symmetric, and f(x,u) is asymptotically linear with respect to u at infinity. Under some technical assumptions on V and f, we prove that the problem (SK) has a positive solution. Copyright © 2013 John Wiley & Sons, Ltd.     

Existence of nontrivial solutions for fractional Schrödinger‐Poisson system with sign‐changing potentials

In this paper, we consider the following fractional Schrödinger‐Poisson system where 0 < t ≤ α < 1, , and 4α+2t ≥3 and the functions V(x), K(x) and f(x) have finite limits as |x|→∞. By imposing some suitable conditions on the decay rate of the functions, we prove that the above system has two nontrivial solutions. One of them is positive and the other one is sign‐changing. Recent results from the literature are generally improved and extended.     

The concentration behavior of ground state solutions for a critical fractional Schrödinger–Poisson system

In this paper, we study the following critical fractional Schrödinger–Poisson system where is a small parameter, and , is the fractional critical exponent for 3‐dimension, has a positive global minimum, and are positive and have global maximums. We obtain the existence of a positive ground state solution by using variational methods, and we determine a concrete set related to the potentials and Q as the concentration position of these ground state solutions as . Moreover, we consider some properties of these ground state solutions, such as convergence and decay estimate.     

Conservative compact finite difference scheme for the coupled Schrödinger–Boussinesq equation

In this article, two conserved compact finite difference schemes for solving the nonlinear coupled Schrödinger–Boussinesq equation are proposed. The conservative property, existence, convergence, and stability of the difference solutions are theoretically analyzed. The numerical results are reported to demonstrate the accuracy and efficiency of the methods and to confirm our theoretical analysis. © 2016Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 32: 1667–1688, 2016     

Ground state solutions for asymptotically periodic fractional Schrödinger–Poisson problems with asymptotically cubic or super‐cubic nonlinearities

In this paper, we consider the following fractional Schrödinger–Poisson problem: where s,t∈(0,1],4s+2t>3,V(x),K(x), and f(x,u) are periodic or asymptotically periodic in x. We use the non‐Nehari manifold approach to establish the existence of the Nehari‐type ground state solutions in two cases: the periodic one and the asymptotically periodic case, by introducing weaker conditions uniformly in with and with constant θ₀∈(0,1), instead of uniformly in and the usual Nehari‐type monotonic condition on f(x,τ)/|τ|³. Our results unify both asymptotically cubic or super‐cubic nonlinearities, which are new even for s=t=1. Copyright © 2017 John Wiley & Sons, Ltd.     

Schrödinger‐Poisson system with Hardy‐Littlewood‐Sobolev critical exponent

In this paper, we consider the following Schrödinger‐Poisson system: where parameters α,β∈(0,3),λ>0, , , and are the Hardy‐Littlewood‐Sobolev critical exponents. For α<β and λ>0, we prove the existence of nonnegative groundstate solution to above system. Moreover, applying Moser iteration scheme and Kelvin transformation, we show the behavior of nonnegative groundstate solution at infinity. For β<α and λ>0 small, we apply a perturbation method to study the existence of nonnegative solution. For β<α and λ is a particular value, we show the existence of infinitely many solutions to above system.     

Maximum error estimates for a compact difference scheme of the coupled nonlinear Schrödinger–Boussinesq equations

The coupled nonlinear Schrödinger–Boussinesq (SBq) equations describe the nonlinear development of modulational instabilities associated with Langmuir field amplitude coupled to intense electromagnetic wave in dispersive media such as plasmas. In this paper, we present a conservative compact difference scheme for the coupled SBq equations and analyze the conservative property and the existence of the scheme. Then we prove that the scheme is convergent with convergence order O(τ² + h⁴) in L_∞‐norm and is stable in L_∞‐norm. Numerical results verify the theoretical analysis.     

Existence and multiplicity results for the nonlinear Schrödinger–Maxwell systems

In this paper, we study the nonlinear Schrödinger–Maxwell system where the potential V and the primitive of g are allowed to be sign‐changing, and g is local superlinear. Under some simple assumptions on V,Q and g, we establish some existence criteria to guarantee that the aforementioned system has at least one nontrivial solution or infinitely many nontrivial solutions by using critical point theory. Recent results in the literature are generalized and significantly improved. Copyright © 2015 John Wiley & Sons, Ltd.     

On 1–dimensional dissipative Schrödinger–type operators their dilations and eigenfunction expansions

In the present paper we characterize the spectrum of small transverse vibrations of an inhomogeneous string with the left end fixed and the right one moving with damping in the direction orthogonal to the equilibrium position of the string. The density of the string is supposed to be smooth and strictly positive everywhere except of an interval of zero density at the right end. Sufficient (close to the necessary) conditions are given for a sequence of complex numbers to be the spectrum of such a string. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Efficient approximation algorithm for the Schrödinger–Possion system

In this article, we study an efficient approximation algorithm for the Schrödinger–Possion system arising in the resonant tunneling diode (RTD) structure. By following the classical Gummel iterative procedure, we first decouple this nonlinear system and prove the convergence of the iteration method. Then via introducing a novel spatial discrete method, we solve efficiently the decoupled Schrödinger and Possion equations with discontinuous coefficients on no‐uniform meshes at each iterative step, respectively. Compared with the traditional ones, the algorithm considered here not only has a less restriction on the discrete mesh, but also is more accurate. Finally, some numerical experiments are shown to confirm the efficiency of the proposed algorithm.     

Standing waves for 4‐superlinear Schrödinger‐Kirchhoff equations

We consider standing waves for 4‐superlinear Schrödinger–Kirchhoff equations in with potential indefinite in sign. The nonlinearity considered in this study satisfies a condition that is much weaker than the classical Ambrosetti–Rabinowitz condition. We obtain a nontrivial solution and, in the case of odd nonlinearity, an unbounded sequence of solutions via the Morse theory and the fountain theorem, respectively. Copyright © 2014 John Wiley & Sons, Ltd.     

Existence of solutions to Schrödinger‐Poisson systems with critical and supercritical nonlinear terms

In this paper, the existence of nontrivial solutions to a class of Schrödinger‐Poisson systems with critical and supercritical nonlinear terms is obtained via variational methods. By using the potential function, a compactness imbedding result is obtained. The properties of potential function play an important role for insuring variational setting.     

Multiple positive solutions for Schrödinger‐Poisson system involving singularity and critical exponent

In this paper, the existence and multiplicity of positive solutions is established for Schrödinger‐Poisson system of the form where 0 ∈ Ω is a smooth bounded domain in , , and λ > 0 is a real parameter. Combining with the variational method and Nehari manifold method, two positive solutions of the system are obtained.     

Two‐grid mixed finite‐element methods for nonlinear Schrödinger equations

Two‐grid mixed finite element schemes are developed for solving both steady state and unsteady state nonlinear Schrödinger equations. The schemes use discretizations based on a mixed finite‐element method. The two‐grid approach yields iterative procedures for solving the nonlinear discrete equations. The idea is to relegate all of the Newton‐like iterations to grids much coarser than the final one, with no loss in order of accuracy. Numerical tests are performed. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 63‐73, 2012     

A Fourier spectral-discontinuous Galerkin method for time-dependent 3-D Schrödinger–Poisson equations with discontinuous potentials

In this paper, we propose a high order Fourier spectral-discontinuous Galerkin method for time-dependent Schrödinger–Poisson equations in 3-D spaces. The Fourier spectral Galerkin method is used for the two periodic transverse directions and a high order discontinuous Galerkin method for the longitudinal propagation direction. Such a combination results in a diagonal form for the differential operators along the transverse directions and a flexible method to handle the discontinuous potentials present in quantum heterojunction and supperlattice structures. As the derivative matrices are required for various time integration schemes such as the exponential time differencing and Crank Nicholson methods, explicit derivative matrices of the discontinuous Galerkin method of various orders are derived. Numerical results, using the proposed method with various time integration schemes, are provided to validate the method.