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A relativistic MOND theory, promising in reproducing cosmology as well as the MOND phenomenology in the low acceleration regime, was recently proposed. We present the post-Newtonian (PN) approximation and relativistic perturbation equations…

General Relativity and Quantum Cosmology · Physics 2025-03-12 Jai-chan Hwang , Hyerim Noh

We present the growing mode solutions of cosmological perturbations to the second order in the matter dominated era. We also present several gauge-invariant combinations of perturbation variables to the second order in most general fluid…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jai-chan Hwang , Hyerim Noh , Jinn-Ouk Gong

In cosmology based on general relativity, the universe is modeled as a fluid. The transition from the Einstein field equation to its large-scale (cosmological) version is thus analogous to the transition, for a system consisting of a large…

General Physics · Physics 2018-10-18 Gregory Ryskin

Semi-analytical methods, based on Eulerian perturbation theory, are a promising tool to follow the time evolution of cosmological perturbations at small redshifts and at mildly nonlinear scales. All these schemes are based on two…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Massimo Pietroni , Gianpiero Mangano , Ninetta Saviano , Matteo Viel

The cosmology of general fourth order corrections to Einstein gravity is considered, both for a homogeneous and isotropic background and for general tensor perturbations. It is explicitly shown how the standard cosmological history can be…

General Relativity and Quantum Cosmology · Physics 2011-03-07 William Nelson

We present a comprehensive Eulerian (Hamiltonian) framework for relativistic fluid dynamics in curved spacetimes, with emphasis on Schwarzschild geometry. The key innovation lies in the consistent use of density and three-velocity fields,…

General Relativity and Quantum Cosmology · Physics 2025-07-23 Arpan Krishna Mitra , Subir Ghosh

We explore possible cosmological consequences of a running Newton's constant $ G ( \Box ) $, as suggested by the non-trivial ultraviolet fixed point scenario in the quantum field-theoretic treatment of Einstein gravity with a cosmological…

General Relativity and Quantum Cosmology · Physics 2011-09-08 Herbert W. Hamber , Reiko Toriumi

Gravitation is described in the context of a dilatonic theory that is conformally related to general relativity. All dimensionless ratios of fundamental dimensional quantities, e.g. particle masses and the Planck mass, as well as the…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-21 Meir Shimon

Special theory of relativity has been formulated in a vacuum momentum-energy representation which is equivalent to Einstein special relativity and predicts just the same results as it. Although in this sense such a formulation would be at…

General Relativity and Quantum Cosmology · Physics 2007-05-23 P. F. Gonzalez-Diaz

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 review the formalism and applications of non-linear perturbation theory (PT) to understanding the large-scale structure of the Universe. We first discuss the dynamics of gravitational instability, from the linear to the non-linear…

Astrophysics · Physics 2008-11-26 F. Bernardeau , S. Colombi , E. Gaztanaga , R. Scoccimarro

Consistency relations involving the soft limit of the (n + 1)-correlator functions of dark matter and galaxy overdensities can be obtained, both in real and redshift space, thanks to the symmetries enjoyed by the Newtonian equations of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Alexandros Kehagias , Jorge Noreña , Hideki Perrier , Antonio Riotto

Energy conservations are studied for inhomogeneous incompressible and compressible Euler equations with general pressure law in a torus or a bounded domain. We provide sufficient conditions for a weak solution to conserve the energy. By…

Analysis of PDEs · Mathematics 2019-09-23 Quoc-Hung Nguyen , Phuoc-Tai Nguyen , Bao Quoc Tang

A hydrodynamic formulation of the evolution of large-scale structure in the Universe is presented. It relies on the spatially coarse-grained description of the dynamical evolution of a many-body gravitating system. Because of the assumed…

Astrophysics · Physics 2009-10-31 Alvaro Dominguez

Motivated by cosmological applications for interacting matters, an extension of the action functional for relativistic fluids is proposed to incorporate the physics of non-adiabatic processes and chemical reactions. The former are…

General Relativity and Quantum Cosmology · Physics 2025-01-30 Damianos Iosifidis , Erik Jensko , Tomi S. Koivisto

This paper is concerned with the global stability of the plane wave solutions to the relativistic string equation with non-small perturbations. Under certain decay assumptions on the plane wave, we conclude that the perturbed system admits…

Analysis of PDEs · Mathematics 2023-11-27 Jinhua Wang , Changhua Wei

A relativistic cosmological perturbation theory for the Friedmann-Lema\^itre-Robertson-Walker universe is presented that explains the masses and formation times of the first structures in our universe. First, it is shown that, without a…

General Relativity and Quantum Cosmology · Physics 2026-04-01 Pieter G. Miedema

We perform three-dimensional simulations of homogeneous and inhomogeneous cosmologies via the coupling of a numerical relativity code for spacetime evolution and smoothed particle hydrodynamics (SPH) code. Evolution of a flat dust and…

General Relativity and Quantum Cosmology · Physics 2023-07-31 Spencer J. Magnall , Daniel J. Price , Paul D. Lasky , Hayley J. Macpherson

A new type of fluid matter model in general relativity is introduced, in which the fluid particles are subject to velocity diffusion without friction. In order to compensate for the energy gained by the fluid particles due to diffusion, a…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Simone Calogero

We calculate the relativistic constraint equation which relates the curvature perturbation to the matter density contrast at second order in cosmological perturbation theory. This relativistic "second order Poisson equation" is presented in…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-13 Juan Carlos Hidalgo , Adam J. Christopherson , Karim A. Malik