广义Duffing扰动振子随机共振机理的渐近解

利用非线性方法研究了一类广义Duffing扰动方程.首先求得了典型的Duffing方程的解.然后利用泛函广义变分迭代原理得到了广义Duffing扰动振子随机共振机理的近似解,并论述了解的一致有效性.     

量子算符的左逆右逆及其数学性质

运用围道积分方法,给出了湮没算符的右逆算符和产生算符的左逆算符;进一步利用湮没算符和产生算符在Fock表象中的矩阵形式对算符的左逆算符、右逆算符的数学性质进行了分析.     

逆算符理论方法及其在非线性物理中的应用

本文系统地综述了近些年来新发展的一种统一求解一大类非线性系统(包括确定论系统及随机性系统)的理论方法──逆算符理论方法及其在非线性物理学中的应用范例,该法无需任何限制假设,具有很大的普适性,我们在计算机上用数学机械化办法实现了它的一些应用,此法能有效地应用于众多学科及领域中,诸如数学、物理、生物、化学、工程技术、医学以及经济等前沿课题及高新科技的研究中,该法具有广阔的应用潜力及发展前景。     

逆算符理论方法及其在非线性物理中的应用

本文系统地综述了近些年来新发展的一种统一解一大类非线性系统（包括确定论系统及随机性系统）的理论方法－逆算符理论方法及其在非线性物理学中的应用范例，该法无需任何限制假设，具有很大的普适性，我们在计算机上用数学机械化办法实现了它的一些应用，此法能有效地应用于众多学科及领域中，诸如数学、物理、生物、化学、工程技术、医学以及经济等前沿课题及高新科技的研究中，该法具有广阔的应用潜力及发展前景。     

利用热纠缠态表象获得Caldeira-Leggett密度算符方程的积分形式解

开放量子系统,即系统-热库模型,可以用一个关于密度算符的主方程来描述,比如,用来描述固态物理中耗散现象的Caldeira.Leggett主方程.虽然已经有人为了求解此主方程的约化密度矩阵的精确表达式而做过一些努力,但迄今还未见有解答.本文使用了一种全新的方法来求解Caldeira-Leggett方程,用这个新方法可以得到积分形式的显式表达.该方法的要点在于利用有序算符内积分技术把关于密度算符的微分方程首先转化成关于密度态矢量的微分方程,再将密度态矢量投影到热纠缠态表象中,Caldeira-Leggett方程就转变成了关于波函数的微分方程,而波函数是函数.这样就可以使用数学中求解微分方程的方法来求解出波函数.再次利用有序算符内积分技术,再将波函数转化为态矢量和算符,就得到了Caldeira-Leggett方程的积分形势解.     

与q形变玻色算符逆算符相关的相干态及其量子统计性质

讨论了ｑ形变玻色算符的广义逆算符作用于ｑ－相干态所得到的两类量子态的数学及量子统计性质。结果表明，ｑ－相干态的光子激发态不存在压缩但呈现反聚束效应，而ｑ－相干态的光子湮灭态却存在压缩但不呈现反聚束效应。     

算符光学中的表象变换及关联方程的普适解法

本文由光学变量算符的线性变换将文献[3]建立的光学矩阵与光学算符的关联方程加以推广,得到光学广义关联方程;又引入本征光学变量算符使其简化成约化光学广义关联方程;从而获得由关联方程求光学点扩散算符的“模拟单透镜成象光路”的普适解法。 关键词：     

耦合广义非线性薛定谔方程的相互作用表象龙格库塔算法及其误差分析

本文通过表象变换, 将耦合广义非线性薛定谔方程 (C-GNLSE) 变换成相互作用表象中的向量方程, 再利用向量形式的4阶龙格-库塔迭代格式, 建立了一种在频域内求解C-GNLSE的同步更新迭代算法. 通过将该向量形式的相互作用表象中的4阶龙格-库塔 (V-JH-RK4IP) 算法应用于高双折射光子晶体光纤中超连续谱产生的数值模拟, 验证了算法的有效性, 通过与现有其他典型算法的比较, 表明以V-JH-RK4IP算法求解C-GNLSE具有最高的计算精度和计算效率. 关键词： 耦合广义非线性薛定谔方程(C-GNLSE) 相互作用表象 4阶龙格-库塔算法 超连续谱产生     

基于Kramers逃逸速率的Duffing振子广义调参随机共振研究

以二维Duffing振子的随机共振为研究对象,提出Duffing振子的广义调参随机共振. 以Kramers逃逸速率为基础,建立了Duffing振子随机共振的判别函数,阐述了Duffing振子在不同噪声强度及信号频率输入条件下的广义调参随机共振规律,并给出了Duffing振子广义调参随机共振的一般方法. 关键词： Duffing振子 随机共振 Kramers逃逸速率 广义参数调节     

一种基于广义Duffing振子的水中弱目标检测方法

海洋环境中,在水下目标的线谱频率未知或者目标辐射噪声的连续谱很弱时,很难实现水中弱目标的准确检测,本文提出基于广义Duffing振子检测系统的水下目标辐射噪声检测方法.通过对传统周期扰动的Duffing振子信号检测系统的分析和推广,提出了一种可输入非周期、非平稳信号的广义Duffing振子检测系统,可检测输入的无先验信息目标信号.为实现广义Duffing振子系统运动状态的精确、有效判断,提出了一种相空间图形的离散分布列计算方法,通过类网格函数实现了利用统计复杂度对系统输出的嵌入式表征,从而实现了无先验信息时的水中弱目标的嵌入式检测.相同条件下与传统检测方法仿真对比可知,本文提出的方法可以检测到更低信噪比下的目标,并能满足水中检测实时性要求.     

New periodic wave solutions via Exp-function method

The Exp-function method with the aid of symbolic computational system is used to obtain the generalized solitary solutions and periodic solutions for nonlinear evolution equations arising in mathematical physics, namely, nonlinear partial differential (BBMB) equation, generalized RLW equation and generalized shallow water wave equation. It is shown that the Exp-function method, with the help of symbolic computation, provides a powerful mathematical tool for solving other nonlinear evolution equations arising in mathematical physics.     

Linearizability conditions for the Rayleigh-like oscillators

In this work we consider a family of nonlinear oscillators that is cubic with respect to the first derivative. Particular members of this family of equations often appear in numerous applications. We solve the linearization problem for this family of equations, where as equivalence transformations we use generalized nonlocal transformations. We explicitly find correlations on the coefficients of the considered family of equations that give the necessary and sufficient conditions for linearizability. We also demonstrate that each linearizable equation from the considered family admits an autonomous Liouvillian first integral, that is Liouvillian integrable. Furthermore, we demonstrate that linearizable equations from the considered family does not possess limit cycles. Finally, we illustrate our results by two new examples of the Liouvillian integrable nonlinear oscillators, namely by the Rayleigh–Duffing oscillator and the generalized Duffing–Van der Pol oscillator.     

表象变换和久期微扰理论在耦合杜芬方程中的应用

本文通过对耦合杜芬方程线性项的表象变换及非线性项的久期微扰理论的应用,将耦合杜芬方程转化为简正表象下的退耦合形式,由此可以很方便地得出耦合杜芬方程的解.为了验证该方法的正确性,设计了音叉耦合实验,观测到了振幅谱谱峰的劈裂以及"振滞回线"现象,这些实验结果都可以和之前所得的理论结果符合得很好.本文求解耦合非线性方程的方法,为灵活运用非线性理论提供一种方案,同时可以推广到光、电等耦合体系,对理解耦合体系的动力学行为具有一定的指导意义.     

New Generalized Transformation Method and Its Application in Higher-Dimensional Soliton Equation

A new generalized transformation method is presented to find more exact solutions of nonlinear partial differential equation. As an application of the method, we choose the (3+1)-dimensional breaking soliton equation to illustrate the method. As a result many types of explicit and exact traveling wave solutions, which contain solitary wave solutions, trigonometric function solutions, Jacobian elliptic function solutions, and rational solutions, are obtained. The new method can be extended to other nonlinear partial differential equations in mathematical physics.     

Application of Exp-function method to Riccati equation and new exact solutions with three arbitrary functions of Broer-Kaup-Kupershmidt equations

In this Letter, the Exp-function method is used to seek generalized solitonary solutions of Riccati equation. Based on the Riccati equation and its generalized solitonary solutions, new exact solutions with three arbitrary functions of the (2+1)-dimensional Broer-Kaup-Kupershmidt equations are obtained. It is shown that the Exp-function method provides a straightforward and important mathematical tool for nonlinear evolution equations in mathematical physics.     

Von mises- and crocco-type hydrodynamical transformations: Order reduction of nonlinear equations,construction of Bäcklund transformations and of new integrable equations

Broad classes of nonlinear equations of mathematical physics are described that admit order reduction by applying the von Mises transformation (with the unknown function used as a new independent variable and with a suitable partial derivative used as a new dependent variable) and by applying the Crocco transformation (with the first and second partial derivatives used as new independent and dependent variables, respectively). Associated Bäcklund transformations are constructed that connect evolution equations of general form (their special cases include Burgers, Korteweg-de Vries, and Harry Dym type equations and many other nonlinear equations of mathematical physics). Transformations are indicated that reduce the order of hydrodynamic-type equations of higher orders. The generalized Calogero equation and a number of other new integrable nonlinear equations, reducible to linear equations, are considered.     

广义(3+1)维Zakharov-Kuznetsov方程的对称约化、精确解和守恒律

运用李群分析,得到了广义(3+1)维Zakharov-Kuznetsov(ZK)方程的对称及约化方程,结合齐次平衡原理,试探函数法和指数函数法得到了该方程的群不变解和新精确解,包括冲击波解、孤立波解等.进一步给出了广义(3+1)维ZK方程的伴随方程和守恒律.     

Structure-preserving algorithms for the Duffing equation

In this paper, the dissipative and the forced terms of the Duffing equation are considered as the perturbations of nonlinear Hamiltonian equations and the perturbational effect is indicated by parameter ε. Firstly, based on the gradient- Hamiltonian decomposition theory of vector fields, by using splitting methods, this paper constructs structure-preserving algorithms （SPAs） for the Duffing equation. Then, according to the Liouville formula, it proves that the Jacobian matrix determinants of the SPAs are equal to that of the exact flow of the Duffing equation. However, considering the explicit Runge Kutta methods, this paper finds that there is an error term of order p＋l for the Jacobian matrix determinants. The volume evolution law of a given region in phase space is discussed for different algorithms, respectively. As a result, the sum of Lyapunov exponents is exactly invariable for the SPAs proposed in this paper. Finally, through numerical experiments, relative norm errors and absolute energy errors of phase trajectories of the SPAs and the Heun method （a second-order Runge-Kutta method） are compared. Computational results illustrate that the SPAs are evidently better than the Heun method when e is small or equal to zero.     

非线性波动方程的孤波解

用平衡法并结合吴消元法得到了一类较广泛非线性波动方程u_tt-a₁u_xx+a₂u_t+a₃u+a₄u³=0的若干孤波解公式，从而物理学上许多著名的方程，如φ⁴方程、Klein-Gordon方程、Landau-Ginzburg-Higgs方程、非线性电报方程等都可作为该方程的特殊情形得到相应的孤波解 关键词：     

CRE Method for Solving m Kd V Equation and New Interactions Between Solitons and Cnoidal Periodic Waves

In nonlinear physics, the modified Korteweg de-Vries(m Kd V) as one of the important equation of nonlinear partial differential equations, its various solutions have been found by many methods. In this paper, the CRE method is presented for constructing new exact solutions. In addition to the new solutions of the m Kd V equation, the consistent Riccati expansion(CRE) method can unearth other equations.