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Models of turbulent flows require the resolution of a vast range of scales, from large eddies to small-scale features directly associated with dissipation. As the required resolution is not within reach of large scale numerical simulations,…

General Relativity and Quantum Cosmology · Physics 2021-10-28 Thomas Celora , Nils Andersson , Ian Hawke , Gregory L. Comer

A number of recent studies have proposed that linear representations are appropriate for solving nonlinear dynamical systems with quantum computers, which fundamentally act linearly on a wave function in a Hilbert space. Linear…

Quantum Physics · Physics 2024-07-10 Yen Ting Lin , Robert B. Lowrie , Denis Aslangil , Yiğit Subaşı , Andrew T. Sornborger

This paper is concerned with error estimates of the fully discrete generalized finite element method (GFEM) with optimal local approximation spaces for solving elliptic problems with heterogeneous coefficients. The local approximation…

Numerical Analysis · Mathematics 2021-10-01 Chupeng Ma , Robert Scheichl

The virtual element method (VEM) allows discretization of the problem domain with polygons in 2D. The polygons can have an arbitrary number of sides and can be concave or convex. These features, among others, are attractive for meshing…

Numerical Analysis · Mathematics 2023-10-06 L. L. Yaw

We introduce a new class of singular partial differential equations, referred to as the second-order hyperbolic Fuchsian systems, and we investigate the associated initial value problem when data are imposed on the singularity. First, we…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Florian Beyer , Philippe G. LeFloch

The paper addresses a numerical method for solving second order elliptic partial differential equations that describe fields inside heterogeneous media. The scope is general and treats the case of rough coefficients, i.e. coefficients with…

Numerical Analysis · Mathematics 2010-11-30 Ivo Babuska , Robert Lipton

A handy technique for the Finite Element Method (FEM) is presented that uses the null space for the implementation of Dirichlet and constraint boundary conditions. The focus of this method is to present an illustrative approach to modeling…

Numerical Analysis · Mathematics 2024-03-12 Stefan Schoder

We provide a full quantization of the vacuum Gowdy model with local rotational symmetry. We consider a redefinition of the constraints where the Hamiltonian Poisson-commutes with itself. We then apply the canonical quantization program of…

General Relativity and Quantum Cosmology · Physics 2017-12-06 Daniel Martín de Blas , Javier Olmedo , Tomasz Pawłowski

Modern applications of strong gravitational lensing require the ability to use precise and varied observational data to constrain complex lens models. I discuss two sets of computational methods for lensing calculations. The first is a new…

Astrophysics · Physics 2007-05-23 Charles R. Keeton

We present the Finite Element Method (FEM) for the numerical solution of the multidimensional coefficient inverse problem (MCIP) in two dimensions. This method is used for explicit reconstruction of the coefficient in the hyperbolic…

Numerical Analysis · Mathematics 2016-03-25 L. Beilina

The finite element simulation of dynamic wetting phenomena, requiring the computation of flow in a domain confined by intersecting a liquid-fluid free surface and a liquid-solid interface, with the three-phase contact line moving across the…

Computational Physics · Physics 2012-02-20 J. E. Sprittles , Y. D. Shikhmurzaev

This paper considers flow problems in multiscale heterogeneous porous media. The multiscale nature of the modeled process significantly complicates numerical simulations due to the need to compute huge and ill-conditioned sparse matrices,…

Numerical Analysis · Mathematics 2024-10-16 Djulustan Nikiforov , Leonardo A. Poveda , Dmitry Ammosov , Yesy Sarmiento , Juan Galvis

In this paper we present an advanced numerical method to simulate a real life challenging industrial problem that consists of the non-destructive testing in steam generators. We develop a finite element technique that handles the big data…

Numerical Analysis · Mathematics 2016-02-11 Mohamed Kamel Riahi

Neural operators (NOs) struggle with high-contrast multiscale partial differential equations (PDEs), where fine-scale heterogeneities cause large errors. To address this, we use the Generalized Multiscale Finite Element Method (GMsFEM) that…

Arguments are made in favor of broadening the scope of the various approaches to splitting spacetime into a single common framework in which measured quantities, derivative operations, and adapted coordinate systems are clearly understood…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Robert T. Jantzen , Paolo Carini , Donato Bini

We provide a complete quantization for the Gowdy model with local rotational symmetry in vacuum. We start with a redefinition of the classical constraint algebra such that the Hamiltonian constraint has a vanishing Poisson bracket with…

General Relativity and Quantum Cosmology · Physics 2017-06-21 Javier Olmedo , Daniel Martín de Blas , Tomasz Pawłowski

A new class of exact solutions of Einstein's field equations with a perfect fluid source, variable gravitational coupling $G$ and cosmological term $\Lambda$ for FRW spacetime is obtained by considering variable deceleration parameter…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Anirudh Pradhan , Ajay Kumar Singh , Saeed Otarod

Accurate numerical simulations of interaction between fluid and solid play an important role in applications. The task is challenging in practical scenarios as the media are usually highly heterogeneous with very large contrast. To overcome…

Numerical Analysis · Mathematics 2020-05-15 Xia Wang , Eric Chung , Shubin Fu , Zhaoqin Huang

We extend the conforming virtual element method to the numerical resolution of eigenvalue problems with potential terms on a polytopal mesh. An important application is that of the Schrodinger equation with a pseudopotential term. This…

Numerical Analysis · Mathematics 2018-04-04 Ondrej Certik , Francesca Gardini , Gianmarco Manzini , Giuseppe Vacca

In this article, we develop a formalism which is different from the standard lensing scenario and is necessary for understanding lensing by gravitational fields which arise as solutions of the effective Einstein equations on the brane. We…

General Relativity and Quantum Cosmology · Physics 2008-12-30 Supratik Pal , Sayan Kar