Non-equilibrium Green’s function (NEGF) is a general method for modeling non-equilibrium quantum transport in open mesoscopic systems with many body scattering effects. In this paper, we present a unified treatment of quantum device boundaries in the framework of NEGF with both finite difference and finite element discretizations. Boundary treatments for both types of numerical methods, and the...

We give a new proof that the El-Mistikawy and Werle finite-difference scheme is uniformly second-order accurate for a nonselfadjoint singularly perturbed boundary value problem. To do this, we use exponential finite elements and a discretized Green's function. The proof is direct, gives the nodal errors explicitly in integral form, and involves much less computation than in previous proofs of t...

Abstract. In this paper, we investigate the dynamic process of liquid bridge formation between two parallel hydrophobic plates with hydrophilic patches, previously studied in [1]. We propose a dynamic Hele-Shaw model to take advantage of the small aspect ratio between the gap width and the plate size. A constrained level set method is applied to solve the model equations numerically, where a gl...

0 = x0 < x1 < . . . xN < xN+1 = 1, xj = jh, j = 0 : N + 1, where h = 1/(N + 1) is the length of each subinterval. Let φi be the hat basis function at xi for i = 0 : N + 1. For a linear finite element function v = ∑N i=1 viφi, we denote by v = (v1, . . . , vN ) the vector formed by the coefficients. The boundary nodes (i = 0, N + 1) are excluded due to the homogenous Dirichlet boundary condition...

This paper is devoted to the numerical analysis of abstract parabolic problem u′ t Au t ; u 0 u0, with hyperbolic generator A. We are developing a general approach to establish a discrete dichotomy in a very general setting in case of discrete approximation in space and time. It is a well-known fact that the phase space in the neighborhood of the hyperbolic equilibrium can be split in a such wa...

In this article we develop convergence theory for a class of goal-oriented adaptive finite element algorithms for second order semilinear elliptic equations. We first introduce several approximate dual problems, and briefly discuss the target problem class. We then review some standard facts concerning conforming finite element discretization and error-estimate-driven adaptive finite element me...

In this paper we develop a technique for avoiding the order reduction caused by nonconstant boundary conditions in the methods called splitting, alternating direction or, more generally, fractional step methods. Such methods can be viewed as the combination of a semidiscrete in time procedure with a special type of additive Runge–Kutta method, which is called the fractional step Runge–Kutta met...

The finite-difference time-domain (FDTD) method is an explicit time discretization scheme for Maxwell’s equations. In this context it is well-known that explicit time discretization schemes have a stability induced time step restriction. In this paper, we recast the spatial discretization of Maxwell’s equations, initially without time discretization, into a more convenient format, called the FD...

This paper deals with the singularly perturbed boundary value problem for a linear second order differential-difference equation of the convection-diffusion type with small delay parameter. A fourth order finite difference method is developed for solving singularly perturbed differential difference equations. To handle the delay argument, we construct a special type of mesh, so that the term co...