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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

We develop a systematic method to obtain the solution of the collisionless Boltzmann equation which describes the growth of large-scale structures as a perturbative series over the initial density perturbations. We give an explicit…

Astrophysics · Physics 2009-11-06 P. Valageas

The evolution of density perturbations is analysed in a modified theory of gravity with a nonminimal coupling between curvature and matter. We consider the broken degeneracy between the choices of matter Lagrangian for a perfect fluid,…

General Relativity and Quantum Cosmology · Physics 2026-01-26 Miguel Barroso Varela , Orfeu Bertolami

A forward model of matter and biased tracers at arbitrary order in Lagrangian perturbation theory (LPT) is presented. The forward model contains the complete LPT displacement field at any given order in perturbations, as well as all…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-04 Fabian Schmidt

We investigate convergence of Lagrangian Perturbation Theory (LPT) by analyzing the model problem of a spherical homogeneous top-hat in an Einstein-deSitter background cosmology. We derive the formal structure of the LPT series expansion,…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-27 Sharvari Nadkarni-Ghosh , David F. Chernoff

We apply the convolved Lagrangian perturbation theory (CLPT) formalism, in which one can express the matter density power spectrum in terms of integrals over a function of cumulants of the displacement field, allowing for a resummation of…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-14 Zvonimir Vlah , Uroš Seljak , Tobias Baldauf

Galaxy surveys demand fast large-scale structure forward models that preserve large-scale phases while providing realistic nonlinear morphology at fixed force resolution. Single-step Lagrangian Perturbation Theory (LPT) solvers are…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-26 Francisco-Shu Kitaura , Francesco Sinigaglia

Structure formation in 1+1 dimensions is considered, with emphasis on the effects of shell-crossing. The breakdown of the perturbative expansion beyond shell-crossing is discussed, and it is shown, in a simple example, that the perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Massimo Pietroni

We discuss various analytical approximation methods for the evolution of the density fluctuation in the Universe. From primordial density fluctuation, the large-scale structure is formed via its own self-gravitational instability. For this…

Astrophysics · Physics 2007-05-23 Takayuki Tatekawa

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

It is shown that a first-order relativistic perturbation theory for the open, flat or closed Friedmann-Lemaitre-Robertson-Walker universe admits one, and only one, gauge-invariant quantity which describes the perturbation to the energy…

General Relativity and Quantum Cosmology · Physics 2014-03-25 P. G. Miedema

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

The nonlinear perturbation theory of gravitational instability is extended to include effects of both biasing and redshift-space distortions, which are inevitable in predicting observable quantities in galaxy surveys. The precise…

Astrophysics · Physics 2014-11-18 Takahiko Matsubara

In the preliminary design of space missions it can be useful to identify regions of dynamics that drive the system's behaviour or separate qualitatively different dynamics. The Lagrangian Coherent Structure (LCS) has been widely used in the…

Earth and Planetary Astrophysics · Physics 2022-09-26 Jack Tyler , Alexander Wittig

We extensively develop a perturbation theory for nonlinear cosmological dynamics, based on the Lagrangian description of hydrodynamics. We solve hydrodynamic equations for a self-gravitating fluid with pressure, given by a polytropic…

Astrophysics · Physics 2009-11-07 Takayuki Tatekawa , Momoko Suda , Kei-ichi Maeda , Masaaki Morita , Hiroki Anzai

The present lecture notes address three columns on which the Lagrangian perturbation approach to cosmological dynamics is based: 1. the formulation of a Lagrangian theory of self--gravitating flows in which the dynamics is described in…

Astrophysics · Physics 2007-05-23 T. Buchert

We discuss a new algorithm to generate multi-scale initial conditions with multiple levels of refinements for cosmological "zoom-in" simulations. The method uses an adaptive convolution of Gaussian white noise with a real space transfer…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Oliver Hahn , Tom Abel

While studying the continual gravitational collapse of a massive matter cloud in general relativity towards examining collapse final states, an important issue is that of whether shell-crossing singularities can develop as the collapse…

General Relativity and Quantum Cosmology · Physics 2013-04-30 Pankaj S. Joshi , Ravindra V. Saraykar

We use both numerical and analytical approaches to study the dynamics of the gravitational collapse in the framework of the relativistic theory of gravitation (RTG). We use various equations of state for the collapsing matter and relatively…

General Relativity and Quantum Cosmology · Physics 2016-09-15 K. V. Antipin , A. I. Dubikovsky , P. K. Silaev

We present a new formulation of Lagrangian perturbation theory which allows accurate predictions of the real- and redshift-space correlation functions of the mass field and dark matter halos. Our formulation involves a non-perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Jordan Carlson , Beth Reid , Martin White