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The dynamic world model and its linear perturbations were first studied in Einstein's gravity. In the system without pressure the relativistic equations coincide exactly with the later known ones in Newton's gravity. Here we prove that,…

General Relativity and Quantum Cosmology · Physics 2009-11-10 J. Hwang , H. Noh

We consider the two-body problem in post-Newtonian approximations of general relativity. We report the recent results concerning the equations of motion, and the associated Lagrangian formulation, of compact binary systems, at the third…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Luc Blanchet

Newtonian N-body simulations have been employed successfully over the past decades for the simulation of the cosmological large-scale structure. Such simulations usually ignore radiation perturbations (photons and massless neutrinos) and…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-07 Julian Adamek , Jacob Brandbyge , Christian Fidler , Steen Hannestad , Cornelius Rampf , Thomas Tram

Inaccuracies in the initial conditions for cosmological N-body simulations could easily be the largest source of systematic error in predicting the non-linear large-scale structure. From the theory side, initial conditions are usually…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-18 Michaël Michaux , Oliver Hahn , Cornelius Rampf , Raul E. Angulo

Perturbation Theory (PT) applied to a cosmological density field with Gaussian initial fluctuations suggests a specific hierarchy for the correlation functions when the variance is small. In particular quantitative predictions have been…

Astrophysics · Physics 2009-10-30 D. Munshi , F. Bernardeau , A. L. Melott , R. Schaeffer

Although bulk peculiar motions are commonplace in the universe, most theoretical studies either bypass them, or take the viewpoint of the idealised Hubble-flow observers. As a result, the role of these peculiar flows remains largely…

General Relativity and Quantum Cosmology · Physics 2021-09-24 C. G. Tsagas , M. I. Kadiltzoglou , K. Asvesta

In this work a study of the gravity is made using Einstein's equation in the post-Newtonian approach. This is a method to linearise the General Relativity indicated to treat non-relativistic objects. It enables us to construct, from…

General Relativity and Quantum Cosmology · Physics 2013-04-29 I. C. Jardim , R. R. Landim

The large-scale statistics of observables such as the galaxy density are chiefly determined by their dependence on the local coarse-grained matter density. This dependence can be measured directly and efficiently in N-body simulations by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Christian Wagner , Fabian Schmidt , Chi-Ting Chiang , Eiichiro Komatsu

In this paper we examine cosmological weak lensing on non-linear scales and show that there are Newtonian and relativistic contributions and that the latter can also be extracted from standard Newtonian simulations. We use the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-06 Daniel B. Thomas , Marco Bruni , David Wands

An experimental formula, sometimes named as Newton-collision-formula, (v1-v2) = - e.(u1-u2) relating relative-velocities before & after impact of two bodies under linear-collision, is commonly used successfully for study of…

General Physics · Physics 2007-05-23 R. C. Gupta , Ruchi Gupta , Sanjay Gupta

The cosmological tests are tight enough now to show that the Friedmann-Lemaitre Lambda CDM cosmological model almost certainly is a useful approximation. This means general relativity theory passes significant tests of the extrapolation of…

Astrophysics · Physics 2017-08-23 P. J. E. Peebles

In modern cosmology, the precision of the theoretical prediction is increasingly required. In cosmological $N$-body simulations, the effect of higher-order Lagrangian perturbation on the initial conditions appears in terms of statistical…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-27 Takayuki Tatekawa

We present a general framework for calculating post-Minskowskian, classical, conservative Hamiltonians for $N$ non-spinning bodies in general relativity from relativistic scattering amplitudes. Novel features for $N>2$ are described…

High Energy Physics - Theory · Physics 2023-03-01 Callum R. T. Jones , Mikhail Solon

This paper presents a comparison of the predictions for the 2 and 3-point correlation functions of density fluctuations, xi_2 and xi_3, in gravitational perturbation theory (PT) against large Cold Dark Matter (CDM) simulations. This…

Astrophysics · Physics 2009-11-07 J. Barriga , E. Gaztanaga

In general relativistic framework of the large scale structure formation theory in the universe, we investigate the relation between density contrast and peculiar velocity in the Newtonian gauge. According to the gauge-invariant property of…

Astrophysics · Physics 2009-11-06 Sohrab Rahvar

In an expanding universe, velocity field and gravitational force field are proportional to each other in the linear regime. Neither of these quantities evolve in time and these can be scaled suitably so that the constant of proportionality…

Astrophysics · Physics 2009-10-28 J. S. Bagla , T. Padmanabhan

The Hamiltonian for a system of relativistic bodies interacting by their gravitational field is found in the post-Minkowskian approximation, including all terms linear in the gravitational constant. It is given in a surprisingly simple…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Tomas Ledvinka , Gerhard Schaefer , Jiri Bicak

$N$-body non efimovian bound or quasi-bound states for particles with short range interactions are considered in arbitrary dimensions. The different resonance regimes near the threshold are depicted by using a generalization of the…

Quantum Gases · Physics 2024-10-09 Ludovic Pricoupenko

We present the second-order expression for the observed redshift, accounting for all the relativistic effects from the light propagation and from the frame change at the observer and the source positions. We derive the generic…

General Relativity and Quantum Cosmology · Physics 2018-09-26 Giuseppe Fanizza , Jaiyul Yoo , Sang Gyu Biern

We construct a self-consistent relativistic Newtonian analogue corresponding to gravitational static spherical symmetric spacetime geometries, staring directly from a generalized scalar relativistic gravitational action in Newtonian…

General Relativity and Quantum Cosmology · Physics 2017-01-25 Shubhrangshu Ghosh , Tamal Sarkar , Arunava Bhadra