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We study linear damped and viscoelastic wave equations evolving on a bounded domain. For both models, we assume that waves are subject to an inhomogeneous Neumann boundary condition on a portion of the domain's boundary. The analysis of…

Analysis of PDEs · Mathematics 2024-10-15 Türker Özsarı , İdem Susuzlu

It is shown that natural boundary conditions for non-relativistic wave functions are of periodic or of homogeneous Robin type. Using asymptotic central symmetry of Hamiltonian and theory of singular differential equations the many-electron…

Quantum Physics · Physics 2015-03-17 Péter V. Tóth

Generalized impedance boundary conditions are effective, approximate boundary conditions that describe scattering of waves in situations where the wave interaction with the material involves multiple scales. In particular, this includes…

Numerical Analysis · Mathematics 2020-05-29 Lehel Banjai , Christian Lubich , Joerg Nick

It is shown using the Gross-Pitaevskii equation that resonance states of Bose-Einstein condensates with attractive interactions can be stabilized into true bound states. A semiclassical variational approximation and an independent quantum…

Soft Condensed Matter · Physics 2007-05-23 Nimrod Moiseyev , L. D. Carr , Boris A. Malomed , Y. B. Band

We revisit the propagation of classical scalar fields in a spacetime which is asymptotically anti-de Sitter. The lack of global hyperbolicity of the underlying background gives rise to an ambiguity in the dynamical evolution of solutions of…

General Relativity and Quantum Cosmology · Physics 2022-04-07 Christyan C. de Oliveira , Ricardo A. Mosna , João Paulo M. Pitelli

An efficient method is proposed for numerical solutions of nonlinear Schr\"{o}dinger equations in an unbounded domain. Through approximating the kinetic energy term by a one-way equation and uniting it with the potential energy equation,…

Numerical Analysis · Mathematics 2009-11-13 Jiwei Zhang , Zhenli Xu , Xiaonan Wu

Solving the 4-d Einstein equations as evolution in time requires solving equations of two types: the four elliptic initial data (constraint) equations, followed by the six second order evolution equations. Analytically the constraint…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Richard A. Matzner

The dynamics of classical field theories is usually governed by field equations, but when fields are constrained to bounded domains it is also dependent on its boundary conditions. Usually boundary conditions are constrained by the…

High Energy Physics - Theory · Physics 2023-10-04 Manuel Asorey , Fernando Ezquerro

This paper is concerned with the boundary-value problem on the Boltzmann equation in bounded domains with diffuse-reflection boundary where the boundary temperature is time-periodic. We establish the existence of time-periodic solutions…

Analysis of PDEs · Mathematics 2018-07-20 Renjun Duan , Yong Wang , Zhu Zhang

While there exist now formulations of initial boundary value problems for Einstein's field equations which are well posed and preserve constraints and gauge conditions, the question of geometric uniqueness remains unresolved. For two…

General Relativity and Quantum Cosmology · Physics 2009-09-28 Helmut Friedrich

Let (M,g) be a compact Einstein manifold with smooth boundary. We consider the spectrum of the p form valued Laplacian with respect to a suitable boundary condition. We show that certain geometric properties of the boundary may be…

Differential Geometry · Mathematics 2007-05-23 JeongHyeong Park

In this paper, we design a series of matching boundary conditions for a two-dimensional compound honeycomb lattice, which has an explicit and simple form, high computing efficiency and good effectiveness of suppressing boundary reflections.…

Numerical Analysis · Mathematics 2024-03-15 Baiyili Liu , Songsong Ji , Gang Pang , Shaoqiang Tang , Lei Zhang

We present a new formulation of the Einstein equations that casts them in an explicitly first order, flux-conservative, hyperbolic form. We show that this now can be done for a wide class of time slicing conditions, including maximal…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Carles Bona , Joan Masso , Edward Seidel , Joan Stela

We show that by adding suitable lower-order terms to the Z4 formulation of the Einstein equations, all constraint violations except constant modes are damped. This makes the Z4 formulation a particularly simple example of a lambda-system as…

General Relativity and Quantum Cosmology · Physics 2020-05-13 Carsten Gundlach , Jose M. Martin-Garcia , Gioel Calabrese , Ian Hinder

Using holographic-fluid techniques, we discuss some aspects of the integrability properties of Einstein's equations in asymptotically anti-de Sitter spacetimes. We review and we amend the results of 1506.04813 on how exact four-dimensional…

High Energy Physics - Theory · Physics 2015-11-16 P. Marios Petropoulos , Konstantinos Siampos

The aim of this work is to study the effect of imposing different types of boundary conditions in the Exner model describing shallow water equations with sedimentation, when a train of waves is imposed at one of the boundaries. The…

Numerical Analysis · Mathematics 2023-03-08 E. Macca , G. Russo

This paper discusses the initial-boundary value problem (with a nonhomogeneous boundary condition) for a multi-dimensional scalar first-order conservation law with a multiplicative noise. One introduces a notion of kinetic formulations in…

Mathematical Physics · Physics 2015-06-19 Kazuo Kobayasi , Dai Noboriguchi

We investigate how the accuracy and stability of numerical relativity simulations of 1D colliding plane waves depends on choices of equation formulations, gauge conditions, boundary conditions, and numerical methods, all in the context of a…

General Relativity and Quantum Cosmology · Physics 2009-11-07 J. M. Bardeen , L. T. Buchman

A conservation-consistent boundary condition is proposed for nonlinear models of soluble-surfactant-laden falling films, ensuring exact conservation of total surfactant mass. The formulation resolves an inconsistency in widely used reduced…

Analysis of PDEs · Mathematics 2026-05-20 Sanghasri Mukhopadhyay , Séverine Millet , Bastien Di Pierro , Asim Mukhopadhyay

We consider the initial boundary value problem for the Einstein vacuum equations in the maximal gauge, or more generally, in a gauge where the mean curvature of a timelike foliation is fixed near the boundary. We prove the existence of…

Analysis of PDEs · Mathematics 2019-12-17 Grigorios Fournodavlos , Jacques Smulevici