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In this communication, we focus on the possibility to test GR with radioscience experiments. We present a new software that in a first step simulates the Range/Doppler signals directly from the space time metric (thus in GR and in…

We construct a consistency test of General Relativity (GR) on cosmological scales. This test enables us to distinguish between the two alternatives to explain the late-time accelerated expansion of the universe, that is, dark energy models…

Astrophysics · Physics 2009-06-23 Yong-Seon Song , Kazuya Koyama

Extensions of Einstein's General Relativity (GR) can formally be given a GR structure in which additional geometric degrees of freedom are mapped on an effective energy-momentum tensor. The corresponding effective cosmic medium can then be…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-11 Winfried Zimdahl , Hermano Velten , William C. Algoner

We use astrophysical data to shed light on fundamental physics by constraining parametrized theoretical cosmological and gravitational models. Gravitational parameters are those constants that parametrize possible departures from Einstein's…

Astrophysics · Physics 2008-08-18 Yi Mao

We review recent developments and results in testing general relativity (GR) at cosmological scales. The subject has witnessed rapid growth during the last two decades with the aim of addressing the question of cosmic acceleration and the…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-09 Mustapha Ishak

Modifications to gravity can provide attractive alternatives to the dark components of the standard model of cosmology. These modifications to general relativity (GR) must be hidden at small scales where theory is well tested, and so one…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-06 Benjamin Bose

General relativistic cosmology cannot be reduced to linear relativistic perturbations superposed on an isotropic and homogeneous (Friedmann-Robertson-Walker) background, even though such a simple scheme has been successfully applied to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Eleonora Villa , Licia Verde , Sabino Matarrese

In this communication, we focus on the possibility to test General Relativity (GR) with radioscience experiments. We present simulations of observables performed in alternative theories of gravity using a software that simulates…

General Relativity and Quantum Cosmology · Physics 2015-03-11 A. Hees , B. Lamine , S. Reynaud , M. -T. Jaekel , C. Le Poncin-Lafitte , V. Lainey , A. Füzfa , J. -M. Courty , V. Dehant , P. Wolf

We address the question of how to build a class of $f(R)$ extensions of General Relativity which are compatible with solar system experiments, without making any preliminary assumption on the properties of $f$. The aim is reached by…

General Relativity and Quantum Cosmology · Physics 2024-09-23 Federico Scali , Oliver Fabio Piattella

We present two methods for describing, from a pedagogical point of view, the solutions of Einstein's equations applied to a homogeneous and isotropic universe. In the first method, we define an effective gravitational potential of the…

Physics Education · Physics 2007-05-23 L. Arturo Ureña--López

We propose two methods for exact Gaussian process (GP) inference and learning on massive image, video, spatial-temporal, or multi-output datasets with missing values (or "gaps") in the observed responses. The first method ignores the gaps…

Machine Learning · Statistics 2018-08-13 Trefor W. Evans , Prasanth B. Nair

General (tele)parallel Relativity, G$_\parallel$R, is the relativistic completion of Einstein's theories of gravity. The focus of this article is the derivation of the homogeneous and isotropic solution in G$_\parallel$R. The…

General Relativity and Quantum Cosmology · Physics 2023-10-18 Débora Aguiar Gomes , Jose Beltrán Jiménez , Tomi S. Koivisto

The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Roustam M. Zalaletdinov

This review is an up-to-date account of the use of numerical relativity to study dynamical, strong-gravity environments in a cosmological context. First, we provide a gentle introduction into the use of numerical relativity in solving…

General Relativity and Quantum Cosmology · Physics 2025-06-24 Josu C. Aurrekoetxea , Katy Clough , Eugene A. Lim

Local conformal transformations are known as a useful tool in various applications of the gravitational theory, especially in cosmology. We describe some new aspects of these transformations, in particular using them for derivation of…

General Relativity and Quantum Cosmology · Physics 2023-06-05 D. F. Carneiro , E. A. Freiras , B. Gonçalves , A. G. de Lima , I. L. Shapiro

This course presents some applications of gravitational lensing to the measurement of masses of galaxies (galaxy-galaxy lensing, Eintein rings, perturbations of giant arcs) and cluster of galaxies (strong and weak lensing). This complements…

Astrophysics · Physics 2007-05-23 Y. Mellier

Einstein's general theory of relativity is the standard theory of gravity, especially where the needs of astronomy, astrophysics, cosmology and fundamental physics are concerned. As such, this theory is used for many practical purposes…

General Relativity and Quantum Cosmology · Physics 2011-08-17 Slava G. Turyshev

Due to the effectiveness of using machine learning in physics, it has been widely received increased attention in the literature. However, the notion of applying physics in machine learning has not been given much awareness to. This work is…

Machine Learning · Computer Science 2022-11-04 Benyamin Ghojogh , Smriti Sharma

In this thesis four separate problems in general relativity are considered, divided into two separate themes: coordinate conditions and perfect fluid spheres. Regarding coordinate conditions we present a pedagogical discussion of how the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Petarpa Boonserm

We propose a model of gravity in which a General Relativity metric tensor and an effective metric generated from a single scalar formulated in Geometric Scalar Gravity are mixed. We show that the model yields the exact Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2016-10-12 Nahomi Kan , Takuya Maki , Kiyoshi Shiraishi