Semi-spectral Chebyshev method in Quantum Mechanics

Traditionally, finite differences and finite element methods have been by many regarded as the basic tools for obtaining numerical solutions in a variety of quantum mechanical problems emerging in atomic, nuclear and particle physics, astrophysics, quantum chemistry, etc. In recent years, however, an alternative technique based on the semi-spectral methods has focused considerable attention. The purpose of this work is first to provide the necessary tools and subsequently examine the efficiency of this method in quantum mechanical applications. Restricting our interest to time independent two-body problems, we obtained the continuous and discrete spectrum solutions of the underlying Schroedinger or Lippmann-Schwinger equations in both, the coordinate and momentum space. In all of the numerically studied examples we had no difficulty in achieving the machine accuracy and the semi-spectral method showed exponential convergence combined with excellent numerical stability.Comment: RevTeX, 12 EPS figure

Multiple Perturbed Collocation Tau Method for Solving Nonlinear Integro-Differential Equations

The purpose of the study was to investigate the numerical solution of non-linear Fredholm and Volterra integro-differential equations by the proposed method called Multiple Perturbed Collocation Tau Method (MPCTM). We assumed a perturbed approximate solution in terms of Chebyshev  polynomial basis function and then determined the derivatives of the perturbed approximate solution which are then substituted into the special classes of the problems considered. Thus, resulting into n-folds integration, the resulting equation is then collocated at equally spaced interior points and the unknown constants in the approximate solution are then obtained by Newton’s method which are then substituted back into the approximate solution.Illustrative examples are given to demonstrate the efficiency, computational cost and accuracy of the method. The results obtained with some numerical examples are compared favorable with some existing numerical methods in literature and with the exact solutions where they are known in closed form.Keywords: Nonlinear Problems, Tau Method, Integro-Differential, Newton’s method

Hybrid functions approach to solve a class of Fredholm and Volterra integro-differential equations

In this paper, we use a numerical method that involves hybrid and block-pulse functions to approximate solutions of systems of a class of Fredholm and Volterra integro-differential equations. The key point is to derive a new approximation for the derivatives of the solutions and then reduce the integro-differential equation to a system of algebraic equations that can be solved using classical methods. Some numerical examples are dedicated for showing efficiency and validity of the method that we introduce

Numerical Solution For Mixed Volterra-Fredholm Integral Equations Of The Second Kind By Using Bernstein Polynomials Method

In this paper, we have used Bernstein polynomials method to solve mixed Volterra-Fredholm integral equations(VFIE’s) of the second kind, numerically. First we introduce the proposed method, then we used it to transform the integral equations to the system of algebraic equations. Finally, the numerical examples illustrate the efficiency and accuracy of this method. Keywords: Bernestein polynomials method, linear Volterra-Fredholm integral equations

Numerical Solutions for Linear Fredholm Integro-Differential Difference Equations with Variable Coefficients by Collocation Methods

We employed an efficient numerical collocation approximation methods to obtain an approximate solution of linear Fredholm integro-differential difference equation with variable coefficients. An assumed approximate solutions for both collocation approximation methods are substituted into the problem considered. After simplifications and collocations, resulted into system of linear algebraic equations which are then solved using MAPLE 18 modules to obtain the unknown constants involved in the assumed solution. The known constants are then substituted back into the assumed approximate solution. Numerical examples were solved to illustrate the reliability, accuracy and efficiency of these methods on problems considered by comparing the numerical solutions obtained with the exact solution and also with some other existing methods. We observed from the results obtained that the methods are reliable, accurate, fast, simple to apply and less computational which makes the valid for the classes of problems considered.   Keywords: Approximate solution, Collocation, Fredholm, Integro-differential difference and linear algebraic equation

Solutions of the Generalized Abel’s Integral Equation using Laguerre Orthogonal Approximation

In this paper, a numerical approximation is drafted for solving the generalized Abel’s integral equation by practicing Laguerre orthogonal polynomials. The proposed approximation is framed for the first and second kinds of the generalized Abel’s integral equation. We have utilized the properties of fractional order operators to interpret Abel’s integral equation as a fractional integral equation. It offers a new approach by employing Laguerre polynomials to approximate the integrand of a fractional integral equation. Given examples demonstrate the simplicity and suitability of the method. The graphical representation of exact and approximate solutions helps in visualizing a solution at discrete points, together with the absolute error function. We have also carried out a numerical comparison with Chebyshev polynomials to display less error in the posed formulation

On The Numerical Solution of Linear Fredholm-Volterra İntegro Differential Difference Equations With Piecewise İntervals

The numerical solution of a mixed linear integro delay differential-difference equation with piecewise interval is presented using the Chebyshev collocation method. The aim of this article is to present an efficient numerical procedure for solving a mixed linear integro delay differential difference equations. Our method depends mainly on a Chebyshev expansion approach. This method transforms a mixed linear integro delay differential-difference equations and the given conditions into a matrix equation which corresponds to a system of linear algebraic equation. The reliability and efficiency of the proposed scheme are demonstrated by some numerical experiments and performed on the computer algebraic system Maple 10