From the Anderson Model on a Strip to the DMPK Equation and Random Matrix Theory

We study weakly disordered quantum wires whose width is large compared to the Fermi wavelength. It is conjectured that such wires display universal metallic behavior as long as their length is shorter than the localization length (which increases with the width). The random matrix theory that accounts for this behavior—the DMPK theory—rests on assumptions that are in general not satisfied by realistic microscopic models. Starting from the Anderson model on a strip, we show that a twofold scaling limit nevertheless allows to recover rigorously the fundaments of DMPK theory, thus opening a way to settle some conjectures on universal metallic behavior.     

General relativity in Newtonian form

It is shown how the use of coordinates where time is measured with clocks moving radially in a spherically symmetric gravitational field leads to general relativistic dynamical expressions that are exactly identical to corresponding expressions in Newtonian theory. The general formalism is developed for the case where the stress-energy tensor is that of a perfect fluid. Expressions like the Newtonian inverse square gravitational law, the Newtonian equation of continuity for fluid flow, Newtonian conservation of energy, etc., follow quite naturally from the fully-fledged exact general relativistic equations. Specific examples involving cosmology and gravitational collapse are given.     

A General Solution of the Fokker-Planck Equation

The Fokker-Planck equation is useful to describe stochastic processes. Depending on the force acting in the system, the solution of this equation becomes complicated and approximate or numerical solutions are needed. The relation with the Schrödinger equation allows building a method to obtain solutions of the Fokker-Planck equation. However, this approach has been limited to the study of confined potentials, restricting its applicability. In this work, we suggest a general treatment for non-confining potentials through the use of series of functions based on the solution of the Schrödinger equation, with part of discrete spectrum and part of continuum spectrum. Two examples, the Rosen-Morse potential and a limited harmonic potential, are analyzed using the suggested approach.     

N-Soliton Solutions of General Nonlinear Schrodinger Equation with Derivative

The bilinear equation of the genera/nonlinear Schrodinger equation with derivative （GDNLSE） and the N-soliton solutions are obtained through the dependent variable transformation and the Hirota method, respectively. The bilinear equation of the nonlinear Schrodinger equation with derivative （DNLSE） and its multisoliton solutions are given by reduction.     

Exact Solutions and Invariant Sets to General Reaction-Diffusion Equation

In this paper, we introduce new invariant sets, and the invariant sets and exact solutions to general reactiondiffusion equation are discussed. It is shown that there exist a class of exact solutions to the equations that belong to the invariant sets.     

General Propagation Lattice Boltzmann Model for the Boussinesq Equation

A general propagation lattice Boltzmann model is used to solve Boussinesq equations. Different local equilibrium distribution functions are selected, and the macroscopic equation is recovered with second order accuracy by means of the Chapman–Enskog multi-scale analysis and the Taylor expansion technique. To verify the effectiveness of the present model, some Boussinesq equations with initial boundary value problems are simulated. It is shown that our model can remain stable and accurate, which is an effective algorithm worthy of promotion and application.     

General Properties of Collision Integral Kernels of the Nonlinear Boltzmann Equation

Technical Physics - We consider general properties of kernels of the inverse collision integral, as well as kernels of integral operators appearing in the expansion of the collision integral in...     

Approximate Generalized Conditional Symmetries for the Perturbed General KdV-Burgers Equation

The approximate generalized conditional symmetry （AGCS） approach we previously proposed [Chin. Phys.Lett. 23 （2006） 527] is applied to study the perturbed general KdV-Burgers （KdVB） equation. Complete classification of those perturbed general KdVB equations which admit certain types of A GCSs is obtained. Approximate solutions to the perturbed equations can be derived from the corresponding unperturbed ones.     

General form of the equation of motion of a charged particle

The most general form of the equation of motion of a charged particle is derived. The equation allows for an arbitrary self-field and is consistent with energy-momentum conservation, angular momentum conservation and the Dirac mass renormalization.     

General form of coupling leading to synchronization of oscillating dynamical systems

There are numerous examples in nature where oscillating or pulsing physical and biological systems automatically synchronize. Here we pose the question: Is there a general type of coupling that leads to such synchronization? It is demonstrated on numerous examples that dissipative coupling results in synchronization for a variety of systems.     

Para-Hamiltonian form for General Autonomous ODE Systems: Introductory Results

We propose a new tool to deal with autonomous ODE systems for which the solution to the Hamiltonian inverse problem is not available in the usual, classical sense. Our approach allows a class of formally conserved quantities to be constructed for dynamical systems showing dissipative behavior and other, more general, phenomena. The only ingredients of this new framework are Hamiltonian geometric mechanics (to sustain certain desirable properties) and the direct reformulation of the notion of the derivative along the phase curve. This seemingly odd and inconsistent marriage of apparently remote ideas leads to the existence of the generator of motion for every autonomous ODE system. Having constructed the generator, we obtained the Lie invariance of the symplectic form ω for free. Various examples are presented, ranging from mathematics, classical mechanics, and thermodynamics, to chemical kinetics and population dynamics in biology. Applications of these ideas to geometric integration techniques of numerical analysis are suggested.     

General form for the longitudinal momentum of a spherically symmetric source

A simple form and its physical interpretation are presented for a solution of the momentum constraint in the initial-value problem of general relativity.     

General form of the full electromagnetic Green function in materials physics

In this article, we present the general form of the full electromagnetic Green function which is suitable for the application in bulk materials physics. In particular, we show how the seven adjustable parameter functions of the free Green function translate into seven corresponding parameter functions of the full Green function. Furthermore, for both the fundamental response tensor and the electromagnetic Green function, we discuss the reduction of the Dyson equation on the four-dimensional Minkowski space to an equivalent, three-dimensional Cartesian Dyson equation.     

General expressions for VM dominated form factors of hadrons fulfilling asymptotic conditions

General expressions for vector-meson dominated (VMD) form factors of hadrons fulfilling asymptotic conditions, derived previously for n vector-meson parameterization of the electromagnetic form factor of any strongly interacting particle with the asymptotics (m < n) and form factor normalization conditions, are presented. The special case of m = n and the expression fulfilling asymptotic conditions without any form factor normalization are discussed too.Received: 27 January 2003, Revised: 31 August 2003, Published online: 27 November 2003     

Master Equation in the General Gauge: On the Problem of Infinite Reducibility

The master equation is quantized. This is an example of quantization of a gauge theory with nilpotent generators. No ghosts are needed for the generation of a gauge algebra. The point about nilpotent generators is that one can not write down a single functional integral for this theory. Instead, one has to write down a product of two coupled functional integrals and take a square root. In a special gauge where the gauge conditions are commuting, the functional integrals decouple and one recovers the known result.     

Soliton Molecule and Breather-Soliton Molecule Structures for a General Sixth-Order Nonlinear Equation

Starting from a general sixth-order nonlinear wave equation,we present its multiple kink solutions,which are related to the famous Hirota form.We also investigate the restrictions on the coefficients of this wave equation for possessing multiple kink structures.By introducing the velocity resonance mechanism to the multiple kink solutions,we obtain the soliton molecule solution and the breather-soliton molecule solution of the sixth-order nonlinear wave equation with particular coefficients.The ...     

A Study for Obtaining New and More General Solutions of Special-Type Nonlinear Equation

The generalized algebraic method with symbolic computation is extended to some special-type nonlinear equations for constructing a series of new and more general travelling wave solutions in terms of special functions. Such equations cannot be directly dealt with by the method and require some kinds of pre-processing techniques. It is shown that soliton solutions and triangular periodic solutions can be established as the limits of the Jacobi doubly periodic wave solutions.     

Conditional Similarity Solutions of （2＋1）—Dimensional General nonintegrable KdV Equation

The real physics models are usually quite complex with some arbitrary parameters which will lead to the nonintegrability of the model.To find some exact solutions of a nonintegrable model with some arbitrary parameters is much more difficult than to find the solutions of a model with some special parameters.In this paper,we make a modification for the usual direct method to find some conditional similarity solutions of a (2 1)-dimensional general nonintegrable KdV equation.