Classification of Positive Ground State Solutions with Different Morse Indices for Nonlinear N-Coupled Schr(o)dinger System

In this paper,we study the following N-coupled nonlinear Schr(o)dinger sys-tem{-△uj+ uj =μju3j + ∑i≠jβi,ju3iuj,in Rn,uj＞0 in Rn,uj(x)→0 as |x|→+∞,j=1,…,N,where n ≤ 3,N ≥ 3,μj ＞ 0,βi,j =βj,i ＞ 0 are constants and βj,j =μj,j =1,…,N.There have been intensive studies for the system on existence/non-existence and clas-sification of ground state solutions when N =2.However fewer results about the classification of ground state solution are available for N ≥ 3.In this paper,we first give a complete classification result on ground state solutions with Morse indices 1,2 or 3 for three-coupled Schr(o)dinger system.Then we generalize our results to N-coupled Schr(o)dinger system for ground state solutions with Morse indices 1 and N.We show that any positive ground state solutions with Morse index 1 or Morse index N must be the form of (d1w,d2w,…,dNw) under suitable conditions,where w is the unique positive ground state solution of certain equation.Finally,we generalize our results to fractional N-coupled Schr(o)dinger system.     

一类Boussinesq方程解的爆破和不稳定性

研究了一类非线性Boussinesq方程解的爆破和基态解的不稳定性,还得到了问题带在不同域中的初值的整体有界解.     

Nonlinear Bound States on Weakly Homogeneous Spaces

We prove the existence of ground state solutions for a class of nonlinear elliptic equations, arising in the production of standing wave solutions to an associated family of nonlinear Schrödinger equations. We examine two constrained minimization problems, which give rise to such solutions. One yields what we call F _λ-minimizers, the other energy minimizers. We produce such ground state solutions on a class of Riemannian manifolds called weakly homogeneous spaces, and establish smoothness, positivity, and decay properties. We also identify classes of Riemannian manifolds with no such minimizers, and classes for which essential uniqueness of positive solutions to the associated elliptic PDE fails.     

Asymptotical behavior of ground state solutions for critical quasilinear Schrödinger equation

This paper is concerned with the existence and asymptotical behavior of positive ground state solutions for a class of critical quasilinear Schrodinger equation.By using a change of variables and variational argument,we prove the existence of positive ground state solution and discuss their asymptotical behavior。     

Existence and multiplicity of positive solutions to Schrödinger–Poisson type systems with critical nonlocal term

The existence, nonexistence and multiplicity of positive radially symmetric solutions to a class of Schrödinger–Poisson type systems with critical nonlocal term are studied with variational methods. The existence of both the ground state solution and mountain pass type solutions are proved. It is shown that the parameter ranges of existence and nonexistence of positive solutions for the critical nonlocal case are completely different from the ones for the subcritical nonlocal system.     

Multiple positive solutions for a Kirchhoff type problem with a critical nonlinearity

In this paper, we study the multiplicity results of positive solutions for a Kirchhoff type problem with critical growth, with the help of the concentration compactness principle, and we prove that problem admits two positive solutions, and one of the solutions is a positive ground state solution.     

带有临界增长的分数阶Kirchhoff方程的半经典解

本文研究如下带有临界增长的分数阶Kirchhoff方程ε^2s(ε^2s-3∫∫R³×R³|u(x)-u(y)/|²|x-y|^3+2s),x∈R³,其中M是一个连续正的Kirchhoff函数,λ>0是一个参数,3/40充分小和λ足够大时,我们首先证明了上述问题正基态解的存在性.其次,证明了基态解集中在一个由位势函数所刻画的特定集合中.最后,研究了基态解的衰减估计.     

Symmetry of translating solutions to mean curvature flows

First, we review the authors' recent results on translating solutions to mean curvature flows in Euclidean space as well as in Minkowski space, emphasizing on the asymptotic expansion of rotationally symmetric solutions. Then we study the sufficient condition for which the translating solution is rotationally symmetric. We will use a moving plane method to show that this condition is optimal for the symmetry of solutions to fully nonlinear elliptic equations without ground state condition.     

A new variational approach to the stability of gravitational systems

We consider the three-dimensional gravitational Vlasov–Poisson system which describes the mechanical state of a stellar system subject to its own gravity. A well-known conjecture in astrophysics is that the steady state solutions which are nonincreasing functions of their microscopic energy are nonlinearly stable by the flow. This was proved at the linear level by Antonov in 1961. Since then, standard variational techniques based on concentration compactness methods as introduced by P.-L. Lions in 1984 have led to the nonlinear stability of subclasses of stationary solutions of ground state type. In this Note, we propose a new variational approach based on the minimization of the Hamiltonian under equimeasurable constraints, which are conserved by the nonlinear transport flow, and recognize any steady state solution which is a nonincreasing function of its microscopic energy as a local minimizer. The outcome is the proof of its nonlinear stability under radially symmetric perturbations. To cite this article: M. Lemou et al., C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

Regularity of ground state solutions of dispersion managed nonlinear schrödinger equations

We consider the dispersion managed nonlinear Schrödinger equation (DMNLS) in the case of zero residual dispersion. Using dispersive properties of the equation and estimates in Bourgain spaces we show that the ground state solutions of DMNLS are smooth. The existence of smooth solutions in this case matches the well-known smoothness of the solutions in the case of nonzero residual dispersion. In the case x∈R² we prove that the corresponding minimization problem with zero residual dispersion has no solution.     

Parametric resonance of ground states in the nonlinear Schrödinger equation

We study the global existence and long-time behavior of solutions of the initial-value problem for the cubic nonlinear Schrödinger equation with an attractive localized potential and a time-dependent nonlinearity coefficient. For small initial data, we show under some nondegeneracy assumptions that the solution approaches the profile of the ground state and decays in time like t^-1/4. The decay is due to resonant coupling between the ground state and the radiation field induced by the time-dependent nonlinearity coefficient.     

Existence and Stability of Solitary Waves of an M-Coupled Nonlinear Schrödinger System

In this paper, the existence and stability results for ground state solutions of an m-coupled nonlinear Schrödinger system $$i\frac{∂}{∂ t}u_j+\frac{∂²}{∂x²}u_j+\sum\limits^m_{i=1}b_{ij}|u_i|^p|u_j|^{p-2}u_j=0,$$ are established, where $2 ≤ m, 2≤p<3$ and $u_j$ are complex-valued functions of $(x,t) ∈ \mathbb{R}^2, j=1,...,m$ and $b_{ij}$ are positive constants satisfying $b_{ij}=b_{ji}$. In contrast with other methods used before to establish existence and stability of solitary wave solutions where the constraints of the variational minimization problem are related to one another, our approach here characterizes ground state solutions as minimizers of an energy functional subject to independent constraints. The set of minimizers is shown to be orbitally stable and further information about the structure of the set is given in certain cases.     

抽象空间中非线性算子方程变号解的存在性研究

利用Banach空间中的锥理论和不动点定理讨论了非线性算子方程变号解的存在性,给出了E_u_0空间下非线性算子方程变号解至少有一个变号解、一个正解和一个负解的条件,并讨论了仅通过一个上解条件得出非线性算子方程变号解的存在性定理.     

一类二阶三点边值问题的解和多解性

利用锥拉伸与锥压缩型Krasnosel'skii不动点定理,给出了一类非线性二阶三点边值问题解和多解的存在性定理,其中允许非线性项有一个负的下界,本文的结论表明该方程可以具有n个解和正解,从而推广和改进了已有的解的存在性的结论.     

A constructive theory for shock-free,isentropic flow

We construct by finite differences solutions of the Cauchy problem for the nonlinear wave equation in one space dimension. We make certain monotonicity assumptions about the initial data, and we show that the resulting solution is Lipschitz continuous for positive times. In addition, we prove the uniqueness of the solution in a certain class, and we characterize its large-time behavior in terms of the equilibrium state for a corresponding Riemann problem. Finally, we show how our results can be extended to more general 2 × 2 systems of hyperbolic conservation laws which are genuinely nonlinear.     

Construction of minimal mass blow-up solutions to rough nonlinear Schrödinger equations

We study the focusing mass-critical rough nonlinear Schrödinger equations, where the stochastic integration is taken in the sense of controlled rough path. In both dimensions one and two, the minimal mass blow-up solutions are constructed, which behave asymptotically like the pseudo-conformal blow-up solutions near the blow-up time. Furthermore, the global well-posedness is obtained if the mass of initial data is below that of the ground state. These results yield that the mass of ground state is exactly the threshold of global well-posedness and blow-up in the stochastic focusing mass-critical case. Similar results are also obtained for a class of nonlinear Schrödinger equations with lower order perturbations, particularly in the absence of the standard pseudo-conformal symmetry and the conservation law of energy.     

On the uniqueness and structure of solutions to a coupled elliptic system

In this paper, we consider a nonlinear elliptic system which is an extension of the single equation derived by investigating the stationary states of the nonlinear Schrödinger equation. We establish the existence and uniqueness of solutions to the Dirichlet problem on the ball. In addition, the nonexistence of the ground state solutions under certain conditions on the nonlinearities and the complete structure of different types of solutions to the shooting problem are proved.     

Global existence for a system of weakly coupled nonlinear Schrödinger equations

This paper discusses the weakly coupled nonlinear Schrödinger equations in the supercritical case. With the best constant of the Gagliardo-Nirenberg inequality, we derive a sufficient condition for the global existence of solutions; this condition is expressed in terms of stationary solutions (nonlinear ground state).     

Asymptotic properties of excited states in the Thomas-Fermi limit

Excited states are stationary localized solutions of the Gross-Pitaevskii equation with a harmonic potential and a repulsive nonlinear term that have zeros on a real axis. The existence and the asymptotic properties of excited states are considered in the semi-classical (Thomas-Fermi) limit. Using the method of Lyapunov-Schmidt reductions and the known properties of the ground state in the Thomas-Fermi limit, we show that the excited states can be approximated by a product of dark solitons (localized waves of the defocusing nonlinear Schrödinger equation with nonzero boundary conditions) and the ground state. The dark solitons are centered at the equilibrium points where a balance between the actions of the harmonic potential and the tail-to-tail interaction potential is achieved.     

Diffusive logistic equation with constant yield harvesting and negative density dependent emigration on the boundary

The structure of positive steady state solutions of a diffusive logistic population model with constant yield harvesting and negative density dependent emigration on the boundary is examined. In particular, a class of nonlinear boundary conditions that depends both on the population density and the diffusion coefficient is used to model the effects of negative density dependent emigration on the boundary. Our existence results are established via the well-known sub-super solution method.