According to one-loop perturbation theory, fermions whose masses are totally generated from Yukawa couplings do not decouple in the heavy mass limit. We investigate this issue nonperturbatively in the strong coupling regime of the chiral U(1) mirror-fermion model in four dimensions. Our numerical results, obtained on 6 · 16, 6 · 24 and 8 · 16 lattices, indicate nondecoupling of heavy fermion an...

A constructive perturbation bound of the Drazin inverse of a square matrix is derived using a technique proposed by G. Stewart and based on perturbation theory for invariant subspaces. This is an improvement of the result published by the authors Wei and Li [Numer. Linear Algebra Appl., 10 (2003), pp. 563–575]. It is a totally new approach to developing perturbation bounds for the Drazin invers...

QED 2 with mass and flavor has in common many features with QCD, and thus is an interesting toy model relevant for four dimensional physics. The model is constructed using Euclidean path integrals and mass perturbation series. The vacuum functional is carefully decomposed into clustering states being the analogue of the θ-vacuum of QCD. Finally the clustering theory can be mapped onto a general...

Recent experimental work has shown that the contrast of near-field optical images depends on the path followed by the tip during the scan. This artifact may misguide the interpretation of the images and the estimation of the optical resolution. We provide a rigorous theoretical study of this effect based on three-dimensional perturbation theory and two-dimensional exact numerical calculations. ...

This note aims at demonstrating the advantage of moving-water well-balanced schemes over still-water well-balanced schemes for the shallow water equations. We concentrate on numerical examples with solutions near a moving-water equilibrium. For such examples, still-water well-balanced methods are not capable of capturing the small perturbations of the moving-water equilibrium and may generate s...

In this paper, we implemented the Modified Iteration Perturbation Method (MIPM) for approximating the periodic behavior of a tapered beam. This problem is formulated as a nonlinear ordinary differential equation with linear and nonlinear terms. The solution is quickly convergent and does not need complicated calculations. Comparing the results of the MIPM with the exact solution shows that this...

We present a perturbation method for determining the moment stability of linear ordinary differential equations with parametric forcing by colored noise. In particular, the forcing arises from passing white noise through an nth order filter. We carry out a perturbation analysis based on a small parameter ε that gives the amplitude of the forcing. Our perturbation analysis is based on a ladder o...

in this paper, we apply the  homotopy analysis method (ham) for solving fuzzy  linear systems and present  the necessary and sufficient conditions for the convergence of series solution obtained via the ham. also, we present a new criterion for choosing a proper value of convergence-control parameter $hbar$ when the ham is applied to linear system of equations. comparisons are made between the ...

in this paper a new form of the homptopy perturbation method is used for solving oscillator differential equation, which yields the maclaurin series of the exact solution. nonlinear vibration problems and differential equation oscillations have crucial importance in all areas of science and engineering. these equations equip a significant mathematical model for dynamical systems. the accuracy o...