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We prove that the Einstein equations can be solved in a very general form for arbitrary spacetime dimensions and various types of vacuum and non-vacuum cases following a geometric method of anholonomic frame deformations for constructing…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Sergiu I. Vacaru

A new computationally efficient method has been introduced to treat self-gravity in mesh based hydrodynamical simulations. It is applied simply by slightly modifying the Poisson equation into an inhomogeneous wave equation. This roughly…

Instrumentation and Methods for Astrophysics · Physics 2016-04-20 Ryosuke Hirai , Hiroki Nagakura , Hirotada Okawa , Kotaro Fujisawa

The aim of this article is to construct initial data for the Einstein equations on manifolds of the form R n+1 x T m , which are asymptotically flat at infinity, without assuming any symmetry condition in the compact direction. We use the…

Analysis of PDEs · Mathematics 2021-11-30 Cécile Huneau , Caterina Vâlcu

We present for astrophysical use a multi-dimensional numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference method on an Eulerian grid, called the Total Variation Diminishing…

Astrophysics · Physics 2016-08-30 Dongsu Ryu , T. W. Jones , Adam Frank

The force-free limit of magnetohydrodynamics (MHD) is often a reasonable approximation to model black hole and neutron star magnetospheres. We describe a general relativistic force-free (GRFFE) formulation that allows general relativistic…

Astrophysics · Physics 2009-11-11 Jonathan C. McKinney

We review recent efforts to re-formulate the Einstein equations for fully relativistic numerical simulations. The so-called numerical relativity (computational simulations in general relativity) is a promising research field matching with…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Hisa-aki Shinkai , Gen Yoneda

The techniques and analysis presented in this thesis provide new methods to solve optimization problems posed on Riemannian manifolds. These methods are applied to the subspace tracking problem found in adaptive signal processing and…

Optimization and Control · Mathematics 2013-05-09 Steven Thomas Smith

Semi-implicit time-stepping schemes for atmosphere and ocean models require elliptic solvers that work efficiently on modern supercomputers. This paper reports our study of the potential computational savings when using mixed precision…

Computational Physics · Physics 2022-10-05 Jan Ackmann , Peter D. Düben , Tim N. Palmer , Piotr K. Smolarkiewicz

We present tests and results of a new axisymmetric, fully general relativistic code capable of solving the coupled Einstein-matter system for a perfect fluid matter field. Our implementation is based on the Bondi metric, by which the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 F. Siebel , J. A. Font , E. Mueller , P. Papadopoulos

Accurate and efficient climate simulations are crucial for understanding Earth's evolving climate. However, current general circulation models (GCMs) face challenges in capturing unresolved physical processes, such as cloud and convection.…

Atmospheric and Oceanic Physics · Physics 2026-01-27 Xin Wang , Jianda Chen , Juntao Yang , Jeff Adie , Simon See , Kalli Furtado , Chen Chen , Troy Arcomano , Romit Maulik , Wei Xue , Gianmarco Mengaldo

This paper describes the main features of a pioneering unsteady solver for simulating ideal two-fluid plasmas on unstructured grids, taking profit of GPGPU (General-purpose computing on graphics processing units). The code, which has been…

The goal of this work is to elaborate on new geometric methods of constructing exact and parametric quasiperiodic solutions for anamorphic cosmology models in modified gravity theories, MGTs, and general relativity, GR. There exist…

General Relativity and Quantum Cosmology · Physics 2017-10-24 Marcelo M. Amaral , Raymond Aschheim , Laurenţiu Bubuianu , Klee Irwin , Sergiu I. Vacaru , Daniel Woolridge

We present \texttt{SACRA-2D}, a new MPI and OpenMP parallelized, fully relativistic hydrodynamics (GRHD) code in dynamical spacetime under axial symmetry with the cartoon method using the finite-volume shock-capturing schemes for…

High Energy Astrophysical Phenomena · Physics 2025-02-06 Alan Tsz-Lok Lam , Masaru Shibata

We consider the relativistic hydrodynamics of non-perfect fluids with the goal of determining a formulation that is suited for numerical integration in special-relativistic and general-relativistic scenarios. To this end, we review the…

General Relativity and Quantum Cosmology · Physics 2023-02-27 Michail Chabanov , Luciano Rezzolla , Dirk H. Rischke

We study geometric relativistic flow and Ricci soliton equations which (for respective nonholonomic constraints and self-similarity conditions) are equivalent to the gravitational field equations of $R^2$ gravity and/or to the Einstein…

General Relativity and Quantum Cosmology · Physics 2016-03-25 Tamara Gheorghiu , Vyacheslav Ruchin , Olivia Vacaru , Sergiu I. Vacaru

Astrophysical relativistic flow problems require high resolution three-dimensional numerical simulations. In this paper, we describe a new parallel three-dimensional code for simulations of special relativistic hydrodynamics (SRHD) using…

Astrophysics · Physics 2009-11-13 Peng Wang , Tom Abel , Weiqun Zhang

Quantum computing presents a promising alternative for the direct simulation of quantum systems with the potential to explore chemical problems beyond the capabilities of classical methods. However, current quantum algorithms are…

Einstein's field equation of General Relativity (GR) has been known for over 100 years, yet it remains challenging to solve analytically in strongly relativistic regimes, particularly where there is a lack of a priori symmetry. Numerical…

General Relativity and Quantum Cosmology · Physics 2017-04-25 Katy Clough

A generalized geometric method is developed for constructing exact solutions of gravitational field equations in Einstein theory and generalizations. First, we apply the formalism of nonholonomic frame deformations (formally considered for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sergiu I. Vacaru

We construct a relativistic resistive magneto-hydrodynamic (RRMHD) numerical simulation code for high-energy heavy-ion collisions. We split the system of differential equations into two parts, a non-stiff and a stiff part. For the non-stiff…

Nuclear Theory · Physics 2023-04-05 Kouki Nakamura , Takahiro Miyoshi , Chiho Nonaka , Hiroyuki R. Takahashi