An algorithm and its application for obtaining some kind of infinite-dimensional Hamiltonian canonical formulation

Using factorization viewpoint of differential operator, this paper discusses how to transform a nonlinear evolution equation to infinite-dimensional Hamiltonian linear canonical formulation. It proves a sufficient condition of canonical factorization of operator, and provides a kind of mechanical algebraic method to achieve canonical ＇σ/σx＇-type expression, correspondingly. Then three examples are given, which show the application of the obtained algorithm. Thus a novel idea for inverse problem can be derived feasibly.

Invertibility of Infinite-Dimensional Hamiltonian Operators and Its Application to Plate Bending Equation

The results of invertibility and spectrum for some different classes of infinite-dimensional Hayniltonian operators, after a brief classification by domains. are given. By the above results, the associated infinite-dimensional Hamiltonian operator with simple supported rectangular plate is proved to be invertible. Furthermore, by a certain compactness, we find that the spectrum of this operator consists only of isolated eigenvalues with finite geometric multiplicity, which will play a significant role in finding the analytical and numerical solution based on Hamiltonian system for a class of plate bending equations.

ORDERED ANALYTIC REPRESENTATION OF PDES BY HAMILTONIAN CANONICAL SYSTEM

Based on the method of symplectic geometry and variational calculation,the method for some PDEs to be ordered and analytically represented by Hamiltonian canonical system is discussed.Meanwhile some related necessary and sufficient conditions are obtained

Spectral Description of a Class of Infinite-Dimensional Hamiltonian Operators and Its Application to Plane Elasticity Equations Without Body Force

In this paper,the results of spectral description and invertibility of upper triangle infinite-dimensionalHamiltonian operators with a diagonal domain are given.By the above results,it is proved that the infinite-dimensionalHamiltonian operator associated with plane elasticity equations without the body force is invertible,and the spectrumof which is non-empty and is a subset of R.

Quantum Systems Connected by a Time-Dependent Canonical Transformation

We study both classical and quantum relation between two Hamiltonian systems which are mutually connected by time-dependent canonical transformation. One is ordinary conservative system and the other is timedependent Hamiltonian system. The quantum unitary operator relevant to classical canonical transformation between the two systems are obtained through rigorous evaluation. With the aid of the unitary operator, we have derived quantum states of the time-dependent Hamiltonian system through transforming the quantum states of the conservative system. The invariant operators of the two systems are presented and the relation between them are addressed. We showed that there exist numerous Hamiltonians, which gives the same classical equation of motion. Though it is impossible to distinguish the systems described by these Hamiltonians within the realm of classical mechanics, they can be distinguishable quantum mechanically.

平面问题混合状态Hamiltonian动力元

本文提出一种对动力学问题的Ｈａｍｉｌｔｏｎ正则方程进行正则变换的方法，并给出一种沿时间方向迭代，沿空间方向半离散半解析求解动力问题Ｈａｍｉｌｔｏｎ正则方程的方法──混合状态Ｈａｍｉｌｔｏｎｉａｎ动力元．

Mindlin层合圆柱壳理论的Hamiltonian结构与辛解析解

通过引进状态变量及其对偶变量。建立Ｍｉｎｄｌｉｎ层合圆柱壳的Ｈａｍｉｌｔｏｎ正则方程．在辛几何数学框架下，采用共轭辛正交归一关系给出各种复杂边界条件下的精确解．

Dressing Multiphoton Hamiltonian

The dressed Hamiltonian describing the multiphoton process is presented by means of a canonical transformation.The exact eigenvalues and eigenstates are given for any set of parameters ω_(0),ω and ε.The general evolution of this system is obtained.

HAMILTONIAN FORMULATION OF NONLINEAR WATER WAVES IN A TWO-FLUID SYSTEM

In this paper, it is dealt with that the Hamiltonian formulation of nonlinear water waves in a two_fluid system,which consists of two layers of constant_density incompressible inviscid fluid with a horizontal bottom,an interface and a free surface. The velocity potentials are expanded in power series of the vertical coordinate. By taking the kinetic thickness of lower fluid_layer and the reduced kinetic thickness of upper fluid_layer as the generalized displacements, choosing the velocity potentials at the interface and free surface as the generalized momenta and using Hamilton's principle, the Hamiltonian canonical equations for the system are derived with the Legendre transformation under the shallow water assumption. Hence the results for single_layer fluid are extended to the case of stratified fluid.

Completeness of system of root vectors of upper triangular infinitedimensional Hamiltonian operators appearing in elasticity theory

This paper deals with a class of upper triangular infinite-dimensional Hamilto- nian operators appearing in the elasticity theory. The geometric multiplicity and algebraic index of the eigenvalue are investigated. Furthermore, the algebraic multiplicity of the eigenvalue is obtained. Based on these properties, the concrete completeness formulation of the system of eigenvectors or root vectors of the Hamiltonian operator is proposed. It is shown that the completeness is determined by the system of eigenvectors of the operator entries. Finally, the applications of the results to some problems in the elasticity theory are presented.

Variational Principles and Hamiltonian Formulation for Nonlinear Water Waves

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Symplectic-like Difference Schemes for Generalized Hamiltonian Systems

The nature of infinite-dimensional Hamiltonian systems are studied for the purpose of further study on some generalized Hamiltonian systems equipped with a given Poisson bracket. From both theoretical and practical viewpoints, we summarize a general method of constructing symplectic-like difference schemes of these kinds of systems. This study provides a new algorithm for the application of the symplectic geometry method in numerical solutions of general evolution equations.

Hamiltonian Formulation for Water Wave Equation

This paper concerns the development and application of the Hamiltonian function which is the sum of kinetic energy and potential energy of the system. Two dimensional water wave equations for irrotational, incompressible, inviscid fluid have been constructed in cartesian coordinates and also in cylindrical coordinates. Then Lagrangian function within a certain flow region is expanded under the assumption that the dispersion μ and the nonlinearity ε satisfied . Using Hamilton’s principle for water wave evolution Hamiltonian formulation is derived. It is obvious that the motion of the system is conservative. Then Hamilton’s canonical equation of motion is also derived.

Any Hamiltonian System Is Locally Equivalent to a Free Particle

In this work we use the Hamilton-Jacobi theory to show that locally all the Hamiltonian systems with n degrees of freedom are equivalent. That is, there is a canonical transformation connecting two arbitrary Hamiltonian systems with the same number of degrees of freedom. This result in particular implies that locally all the Hamiltonian systems are equivalent to that of a free particle. We illustrate our result with two particular examples;first we show that the one-dimensional free particle is locally equivalent to the one-dimensional harmonic oscillator and second that the two-dimensional free particle is locally equivalent to the two-dimensional Kepler problem.

Completeness of the System of Root Vectors of 2×2 Upper Triangular Infinite-Dimensional Hamiltonian Operators in Symplectic Spaces and Applications

The authors investigate the completeness of the system of eigen or root vectors of the 2×2 upper triangular infinite-dimensional Hamiltonian operator H 0.First,the geometrical multiplicity and the algebraic index of the eigenvalue of H0 are considered.Next,some necessary and sufficient conditions for the completeness of the system of eigen or root vectors of H0 are obtained.Finally,the obtained results are tested in several examples.

一些数学物理问题中的Hamilton方程

讨论了新的一系列在数学物理方程中微分方程的Hamilton正则表示 ,其中包括变系数 2阶对称方程的Hamilton系统 ,关于常系数的 4阶对称方程新的非齐次Hamilton表示 ,MKdV方程以及KP方程的正则表示·

Poisson流形上广义Hamilton系统的保结构算法

Poisson流形是研究广义 Hamilton系统的恰当几何结构。本文在 Poisson流形上讨论广义Hamilton系统的保结构的数值解法 ,为广义 Hamilton系统的数值计算提供了理论基础。文中通过算例证明了算法的保结构性和稳定性 ,同时说明了该算法可以推广到广义 Hamilton控制系统。

一个二流体系统中非线性水波的Hamilton描述

讨论了一个二流体系统中非线性水波的Ｈａｍｉｌｔｏｎ描述，该系统由水平固壁之上的两层常密度不可压无粘流体组成，上表面为自由面·文中将速度势函数展开成垂向坐标的幂级数，在浅水长波的假定下，取下层流体的“动厚度”与上层流体的“折合动厚度”为广义位移、界面上和自由面上的速度势为广义动量，根据Ｈａｍｉｌｔｏｎ原理并运用Ｌｅｇｅｎｄｒｅ变换导出该系统的Ｈａｍｉｌｔｏｎ正则方程，从而将单层流体情形的结果推广到分层流体的情形·

基于哈密顿解法的矩形厚板分析

建立了分析Reissner-Mindlin厚板问题的哈密顿解法。首先,以x坐标模拟时间坐标,选用互为对偶的混合变量作为基本变量,建立哈密顿正则微分方程组。然后,采用分离变量法和特征函数展开法在相应的边界条件下求出级数解。最后,给出矩形厚板典型例题的解答,分析了级数解的收敛性质。与常用的半逆解法相比,Hamilton解法有其优点:一是求解方法严密合理、有规可循;二是应用范围广,可用于求解系列问题。

基础隔震框架结构动力时程分析的精细积分法

为了求得基础隔震框架结构抗震性能的高精度数值解,基于层剪切模型建立了结构的动力方程。引入对偶变量,导出动力时程分析的哈密顿正则方程,应用初值问题的精细积分法求得数值解;最后应用MATLAB语言编制程序对一应用橡胶垫基础的6层框架结构进行多遇地震作用下的动力时程分析。计算结果表明,在相同的地震波作用下,相对于传统抗震结构,基础隔震结构的层间位移减少了60%,速度和加速度减少了30%,顶层最大位移减少了15%。由此可见,基础隔震结构具有优良的抗震性能。该方法是求解基础隔震框架结构动力时程分析的新方法,计算数据精度高、可靠性好。