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Absorbing boundary conditions are presented for three-dimensional time-dependent Schr\"odinger-type of equations as a means to reduce the cost of the quantum-mechanical calculations. The boundary condition is first derived from a…

Numerical Analysis · Mathematics 2020-01-15 Xiaojie Wu , Xiaotao Li

We formulate a time-dependent density functional theory (TDDFT) in terms of the density matrix to study ultrafast phenomena in semiconductor structures. A system of equations for the density matrix components, which is equivalent to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 V. Turkowski , C. A. Ullrich

Absorbing layers are sometimes required to be impractically thick in order to offer an accurate approximation of an absorbing boundary condition for the Helmholtz equation in a heterogeneous medium. It is always possible to reduce an…

Numerical Analysis · Mathematics 2014-08-15 Rosalie Bélanger-Rioux

A common approach for the numerical simulation of wave propagation on a spatially unbounded domain is to truncate the domain via an artificial boundary, thus forming a finite computational domain with an outer boundary. Absorbing boundary…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Olivier Sarbach

Time-dependent density functional theory is widely used to describe excitations of many-fermion systems. In its many applications, 3D coordinate-space representation is used, and infinite-domain calculations are limited to a finite volume…

Nuclear Theory · Physics 2016-05-11 B. Schuetrumpf , W. Nazarewicz , P. -G. Reinhard

Absorbing layers are sometimes required to be impractically thick in order to offer an accurate approximation of an absorbing boundary condition for the Helmholtz equation in a heterogeneous medium. It is always possible to reduce an…

Numerical Analysis · Mathematics 2014-01-20 Rosalie Bélanger-Rioux , Laurent Demanet

This paper proposes a new method, in the frequency domain, to define absorbing boundary conditions for general two-dimensional problems. The main feature of the method is that it can obtain boundary conditions from the discretized equations…

Classical Physics · Physics 2015-05-14 Denis Duhamel , Tien-Minh Nguyen

Time-dependent density-functional theory (TDDFT) is a central tool for studying the dynamical electronic structure of molecules and solids, yet aspects of its mathematical foundations remain insufficiently understood. In this work, we…

Absorbing boundaries are frequently employed in real-time propagation of the Schr\"odinger equation to remove spurious reflections and efficiently emulate outgoing boundary conditions. These conditions are a fundamental ingredient for an…

Computational Physics · Physics 2015-02-09 Umberto De Giovannini , Ask Hjorth Larsen , Angel Rubio

We present an efficient method for propagating the time-dependent Kohn-Sham equations in free space, based on the recently introduced Fourier contour deformation (FCD) approach. For potentials which are constant outside a bounded domain,…

Chemical Physics · Physics 2023-07-10 Jason Kaye , Alex Barnett , Leslie Greengard , Umberto De Giovannini , Angel Rubio

A new type of absorbing boundary conditions for molecular dynamics simulations are presented. The exact boundary conditions for crystalline solids with harmonic approximation are expressed as a dynamic Dirichlet- to-Neumann (DtN) map. It…

Computational Physics · Physics 2017-10-27 Xiaojie Wu , Xiantao Li

Real-Time Time-Dependent Density Functional Theory (TDDFT) has become an attractive tool to model quantum dynamics on a first-principles Density Functional Theory level. In recent years, several developments and applications in this field…

Computational Physics · Physics 2020-08-21 Joscha Hekele , Peter Kratzer

We present a new formulation of the multipolar expansion of an exact boundary condition for the wave equation, which is truncated at the quadrupolar order. Using an auxiliary function, that is the solution of a wave equation on the sphere…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Jerome Novak , Silvano Bonazzola

An approximate method based on adiabatic time dependent density functional theory (TDDFT) is presented, that allows for the description of the electron dynamics in nanoscale junctions under arbitrary time dependent external potentials. In…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Y. Wang , C. -Y. Yam , G. H. Chen , Th. Frauenheim , T. A. Niehaus

We formulate a time-dependent density-matrix functional theory (TDDMFT) approach for higher-order correlation effects like biexcitons in optical processes in solids based on the reduced two-particle density-matrix formalism within the…

Materials Science · Physics 2015-05-19 Volodymyr Turkowski , Carsten A. Ullrich , Talat S. Rahman , Michael N. Leuenberger

We provide a new formulation of Time-Dependent Density Functional Theory (TDDFT) based on the geometric structure of the set of states constrained to have a fixed density. Orbital-free TDDFT is formulated using a hydrodynamics equation…

We propose a formulation of an absorbing boundary for a quantum particle. The formulation is based on a Feynman-type integral over trajectories that are confined to the non-absorbing region. Trajectories that reach the absorbing wall are…

Quantum Physics · Physics 2009-10-30 A. Marchewka , Z. Schuss

Time-dependent density-functional theory (TDDFT) is a computationally efficient first-principles approach for calculating optical spectra in insulators and semiconductors, including excitonic effects. We show how exciton wave functions can…

Materials Science · Physics 2020-12-29 Jared R. Williams , Nicolas Tancogne-Dejean , Carsten A. Ullrich

The paper presents an automatic generator of approximate nonreflecting boundary conditions, analytical and numerical, for scalar wave equations. This generator has two main ingredients. The first one is a set of local Trefftz functions --…

Numerical Analysis · Mathematics 2014-06-03 Igor Tsukerman

We introduce a new class of absorbing boundary conditions (ABCs) for the Helmholtz equation. The proposed ABCs are obtained by using $L$ discrete layers and the $Q_N$ Lagrange finite element in conjunction with the $N$-point Gauss-Legendre…

Numerical Analysis · Mathematics 2024-05-07 Koki Sagiyama
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