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The tree code for the approximate evaluation of gravitational forces is extended and substantially accelerated by including mutual cell-cell interactions. These are computed by a Taylor series in Cartesian coordinates and in a completely…

Astrophysics · Physics 2009-10-31 Walter Dehnen

The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Vitor Cardoso , Leonardo Gualtieri , Carlos Herdeiro , Ulrich Sperhake

There are many complementary approaches to the construction of solutions to the field equations of general relativity. Among these, numerical approximation offers the only possibility to compute a variety of dynamical spacetimes, and so has…

General Relativity and Quantum Cosmology · Physics 2024-05-13 David Hilditch

We present three-dimensional simulations of Einstein equations implementing a symmetric hyperbolic system of equations with dynamical lapse. The numerical implementation makes use of techniques that guarantee linear numerical stability for…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Manuel Tiglio , Luis Lehner , David Neilsen

An exact solution to a family of parity check error-correcting codes is provided by mapping the problem onto a Husimi cactus. The solution obtained in the thermodynamic limit recovers the replica symmetric theory results and provides a very…

Disordered Systems and Neural Networks · Physics 2009-10-31 Renato Vicente , David Saad , Yoshiyuki Kabashima

The problem of realizing finite metric spaces in terms of weighted graphs has many applications. For example, the mathematical and computational properties of metrics that can be realized by trees have been well-studied and such research…

Combinatorics · Mathematics 2020-02-10 Momoko Hayamizu , Katharina T. Huber , Vincent Moulton , Yukihiro Murakami

We perform three-dimensional numerical relativity simulations of homogeneous and inhomogeneous expanding spacetimes, with a view towards quantifying non-linear effects from cosmological inhomogeneities. We demonstrate fourth-order…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Hayley J. Macpherson , Paul D. Lasky , Daniel J. Price

A new numerical scheme to solve the Einstein field equations based upon the generalized harmonic decomposition of the Ricci tensor is introduced. The source functions driving the wave equations that define generalized harmonic coordinates…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Frans Pretorius

The simplest flavor of the Effective Field Theory of Large Scale Structure is based on Newtonian equations and describes the nonlinear matter density and velocity using Einstein-de-Sitter kernels. Even in the presence of massive neutrinos,…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-07 Christian Fidler , Julien Lesgourgues , Antonia Mattes , Azadeh Moradinezhad Dizgah , Simon Neuland

The quantum field theoretic prediction for the vacuum energy density leads to a value for the effective cosmological constant that is incorrect by between 60 to 120 orders of magnitude. We review an old proposal of replacing Einstein's…

General Relativity and Quantum Cosmology · Physics 2011-10-24 George F. R. Ellis , Henk van Elst , Jeff Murugan , Jean-Philippe Uzan

The application of numerical relativity to cosmological spacetimes is providing new insights into the behavior of Einstein's equations, beyond common approximations. In order for simulations to be performed as accurately and efficiently as…

General Relativity and Quantum Cosmology · Physics 2017-10-25 John T. Giblin , James B. Mertens , Glenn D. Starkman

This is the second paper in a series describing a numerical implementation of the conformal Einstein equation. This paper deals with the technical details of the numerical code used to perform numerical time evolutions from a "minimal" set…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Peter Huebner

In this paper I investigate the possibility to test Einstein's equations with observations of cosmological large scale structure. I first show that we have not tested the equations in observations concerning only the homogeneous and…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-31 Ruth Durrer

We study the stability of three-dimensional numerical evolutions of the Einstein equations, comparing the standard ADM formulation to variations on a family of formulations that separate out the conformal and traceless parts of the system.…

The applications of numerical relativity to cosmology are on the rise, contributing insight into such cosmological problems as structure formation, primordial phase transitions, gravitational-wave generation, and inflation. In this paper, I…

General Relativity and Quantum Cosmology · Physics 2017-03-08 Eloisa Bentivegna

In Einstein's general relativity, with its nonlinear field equations, the discoveries and analyzes of various specific explicit solutions made a great impact on understanding many of the unforeseen features of the theory. Some solutions…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jiri Bicak

We study the three dimensional Einstein gravity conformally coupled to a scalar field. Solutions of this theory are geometries with vanishing scalar curvature. We consider solutions with a constant scalar field which corresponds to an…

High Energy Physics - Theory · Physics 2012-11-08 M. Hasanpour , F. Loran , H. Razaghian

We perform simulations in a gravitational collapsing model using the Einstein equations. In this paper, we review the equations for constructing the initial values and the evolution form of the Einstein equations called the BSSN…

General Relativity and Quantum Cosmology · Physics 2022-07-07 Takuya Tsuchiya , Ryosuke Urakawa , Gen Yoneda

A number of codes for general-relativistic simulations of cosmological structure formation have been developed in recent years. Here we demonstrate that a sample of these codes produce consistent results beyond the Newtonian regime. We…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-20 Julian Adamek , Cristian Barrera-Hinojosa , Marco Bruni , Baojiu Li , Hayley J. Macpherson , James B. Mertens

In these proceedings, we review recent advances in applying quantum computing to lattice field theory. Quantum computing offers the prospect to simulate lattice field theories in parameter regimes that are largely inaccessible with the…

High Energy Physics - Lattice · Physics 2023-08-10 Lena Funcke , Tobias Hartung , Karl Jansen , Stefan Kühn