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We develop a new nonlinear method to model structure formation in general relativity from a generalization of the relativistic Lagrangian perturbation schemes, controlled by Szekeres (and LTB) exact solutions. The overall approach can be…

General Relativity and Quantum Cosmology · Physics 2023-01-19 Ismael Delgado Gaspar , Thomas Buchert , Jan J. Ostrowski

The Newtonian Lagrangian perturbation theory is a widely used framework to study structure formation in cosmology in the nonlinear regime. We review a general-relativistic formulation of such a perturbation approach, emphasizing results on…

General Relativity and Quantum Cosmology · Physics 2022-11-10 Thomas Buchert , Ismael Delgado Gaspar , Jan J. Ostrowski

In this first paper we present a Lagrangian framework for the description of structure formation in general relativity, restricting attention to irrotational dust matter. As an application we present a self-contained derivation of a…

General Relativity and Quantum Cosmology · Physics 2012-07-24 Thomas Buchert , Matthias Ostermann

Approximations to the exact solutions for gravitational instability in the expanding Universe are extremely useful for understanding the evolution of large--scale structure. We report on a series of tests of Newtonian Lagrangian…

Astrophysics · Physics 2007-05-23 T. Buchert , A. L. Melott , A. G. Weiss

Kinematical and dynamical properties of a generic inhomogeneous cosmological model, spatially averaged with respect to free-falling (generalized fundamental) observers, are investigated for the matter model irrotational dust. Paraphrasing a…

General Relativity and Quantum Cosmology · Physics 2013-06-12 Thomas Buchert , Charly Nayet , Alexander Wiegand

The gravitational instability of inhomogeneities in the expanding universe is studied by the relativistic second-order approximation. Using the tetrad formalism we consider irrotational dust universes and get equations very similar to those…

Astrophysics · Physics 2009-10-28 H. Russ , M. Morita , M. Kasai , G. Boerner

Previous work in the literature has studied the Hamiltonian structure of an R-squared model of gravity with torsion in a closed Friedmann-Robertson-Walker universe. Within the framework of Dirac's theory, torsion is found to lead to a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Giampiero Esposito , Gabriele Gionti , Giuseppe Marmo , Cosimo Stornaiolo

This paper deals with the time evolution in the matter era of perturbations in Friedman-Lemaitre models with arbitrary density parameter $\Omega$, with either a zero cosmological constant, $\Lambda = 0$, or with a non-zero cosmological…

Astrophysics · Physics 2011-05-23 F. R. Bouchet , S. Colombi , E. Hivon , R. Juszkiewicz

We investigate the Lagrangian perturbation theory of a homogeneous and isotropic universe in the non-relativistic limit, and derive the solutions up to the fourth order. These solutions are needed for example for the next-to-leading order…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-15 Cornelius Rampf , Thomas Buchert

The relativistic generalization of the Newtonian Lagrangian perturbation theory is investigated. In previous works, the perturbation and solution schemes that are generated by the spatially projected gravitoelectric part of the Weyl tensor…

General Relativity and Quantum Cosmology · Physics 2018-01-01 Fosca Al Roumi , Thomas Buchert , Alexander Wiegand

We derive a recursion relation in the framework of Lagrangian perturbation theory, appropriate for studying the inhomogeneities of the large scale structure of the universe. We use the fact that the perturbative expansion of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-27 Cornelius Rampf

In standard perturbation approaches and N-body simulations, inhomogeneities are described to evolve on a predefined background cosmology, commonly taken as the homogeneous-isotropic solutions of Einstein's field equations…

General Relativity and Quantum Cosmology · Physics 2012-05-11 Xavier Roy , Thomas Buchert

The exact Friedman solution to the field equations of General Relativity (GR) describing a homogeneous and isotropic universe together with its linear and higher-order perturbations are the theoretical roots of the current standard model of…

General Relativity and Quantum Cosmology · Physics 2024-12-20 Marie-Noëlle Célérier

Structure formation in the Universe has been well-studied within the Eulerian and Lagrangian perturbation theories, where the latter performs substantially better in comparison with N-body simulations. Standing out is the celebrated…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-04 Niels Fardeau , Thomas Buchert , Fosca Al Roumi , Fereshteh Felegary

We extend the general relativistic Lagrangian perturbation theory, recently developed for the formation of cosmic structures in a dust continuum, to the case of model universes containing a single fluid with a single-valued analytic…

General Relativity and Quantum Cosmology · Physics 2018-08-10 Yong-Zhuang Li , Pierre Mourier , Thomas Buchert , David L. Wiltshire

The Lagrangian theory of structure formation in cosmological fluids, restricted to the matter model ``dust'', provides successful models of large-scale structure in the Universe in the laminar regime, i.e., where the fluid flow is…

Astrophysics · Physics 2011-05-23 Susanne Adler , Thomas Buchert

At a time when galaxy surveys and other observations are reaching unprecedented sky coverage and precision it seems timely to investigate the effects of general relativistic nonlinear dynamics on the growth of structures and on…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-04 Nikolai Meures , Marco Bruni

We study the nonlinear gravitational dynamics of a universe filled with a pressureless fluid and a cosmological constant $\Lambda$ in the context of Newtonian gravity, and in the relativistic post-Friedmann approach proposed in paper I [I.…

General Relativity and Quantum Cosmology · Physics 2016-10-26 Cornelius Rampf , Eleonora Villa , Daniele Bertacca , Marco Bruni

Recently a new Lagrangian framework was introduced to describe interactions between scalar fields and relativistic perfect fluids. This allows two consistent generalizations of coupled quintessence models: non-vanishing pressures and a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Tomi S. Koivisto , Emmanuel N. Saridakis , Nicola Tamanini

We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of quasilinear scales. The Lagrangian theory of gravitational instability of an Einstein-de…

Astrophysics · Physics 2007-05-23 T. Buchert , A. L. Melott , A. G. Weiss
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