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Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the universe. We calculate quasilinear effects in the growth of structure in f(R) models of gravity using perturbation…

Astrophysics · Physics 2009-10-29 Alex Borisov , Bhuvnesh Jain

In this manuscript, we studied the accelerated expansion history of the universe and the formations of large-scale structures using $f(Q)$ gravity model. The expansion rate of the universe within distance modulus and redshift has been…

General Relativity and Quantum Cosmology · Physics 2022-06-07 Shambel Sahlu , Endalkachew Tsegaye

We investigate the transfer of power between different scales and coupling of modes during non-linear evolution of gravitational clustering in an expanding universe. We start with a power spectrum of density fluctuations that is…

Astrophysics · Physics 2015-06-24 J. S. Bagla , T. Padmanabhan

We discuss a class of teleparallel scalar-torsion theories of gravity, which is parametrized by five free functions of the scalar field. The theories are formulated covariantly using a flat, but non-vanishing spin connection. We show how…

General Relativity and Quantum Cosmology · Physics 2018-09-12 Manuel Hohmann

The present acceleration of the Universe strongly indicated by recent observational data can be modeled in the scope of a scalar-tensor theory of gravity. We show that it is possible to determine the structure of this theory (the scalar…

General Relativity and Quantum Cosmology · Physics 2009-10-31 B. Boisseau , G. Esposito-Farese , D. Polarski , A. A. Starobinsky

We consider generalized teleparallel gravity in the flat FRW universe with a viable power-law f(T) model. We construct its equation of state and deceleration parameters which give accelerated expansion of the universe in quintessence era…

General Physics · Physics 2015-06-18 M. Sharif , Shamaila Rani

Scalar-tensor theory of gravity with non-minimal coupling is a fairly good candidate for dark energy, required to explain late-time cosmic evolution. Here we study the very early stage of evolution of the universe with a modified version of…

High Energy Physics - Theory · Physics 2018-05-22 Ranajit Mandal , Chandramouli Sarkar , Abhik Kumar Sanyal

Is gravitational growth responsible for the observed large scale structure in the universe? Do we need non-gaussian initial conditions or non-gravitational physics to explain the large scale features traced by galaxy surveys? I will briefly…

Astrophysics · Physics 2007-05-23 Enrique Gaztanaga

In this work, we further investigate the family of $f(R)$ dark energy models that can exactly mimic the same background expansion history as that of the $\Lambda$CDM model. We study the large scale structure in the $f(R)$ gravity using the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jian-hua He

We take into account redshift-space distortion measurements to investigate the growth of cosmological large-scale structures within the framework of modified symmetric teleparallel $f(Q)$ gravity. After comparing the predictions of the…

General Relativity and Quantum Cosmology · Physics 2025-03-20 Shambel Sahlu , Álvaro de la Cruz-Dombriz , Amare Abebe

The genus of the iso-density contours is a robust measure of the topology of large scale structure, and it is relatively insensitive to nonlinear gravitational evolution, galaxy bias and redshift-space distortion. We show that the growth of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Xin Wang , Xuelei Chen , Changbom Park

These lecture notes introduce analytical tools, methods and results describing the growth of cosmological structure beyond the linear regime. The presentation is focused on the single flow regime of the Vlasov-Poisson equation describing…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-03 Francis Bernardeau

The computation of the spectrum of primordial perturbations, generated by a scalar field during the super-inflationary phase of Loop Quantum Cosmology, is revisited. The calculation is performed for two different cases. The first considers…

Astrophysics · Physics 2009-11-11 D. J. Mulryne , N. J. Nunes

We derive the power spectrum of primordial quantum fluctuations in an inflationary universe for curvature parameter ${\mathcal K}=1$. This is achieved through a Born--Oppenheimer type of approximation scheme from the Wheeler--DeWitt…

General Relativity and Quantum Cosmology · Physics 2022-04-05 Claus Kiefer , Tatevik Vardanyan

We discuss the constraints imposed on the nonlinear evolution of the Large Scale Structure (LSS) of the universe by galilean invariance, the symmetry relevant on subhorizon scales. Using Ward identities associated to the invariance, we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Marco Peloso , Massimo Pietroni

The angular power spectra of cosmic microwave background are analyzed under the light of the evolutional scenario of the universe based on the renormalizable quantum theory of gravity in four dimensions. The equation of evolution is solved…

Astrophysics · Physics 2009-11-13 Ken-ji Hamada , Shinichi Horata , Naoshi Sugiyama , Tetsuyuki Yukawa

We calculate the scalar power spectrum generated by sourced fluctuations due to coupling between the scalar field, which holds most of the energy density of the universe, and a gauge field for a general FLRW metric. For this purpose we…

General Relativity and Quantum Cosmology · Physics 2021-02-19 Ido Ben-Dayan , Judy Kupferman

Distances in cosmology are usually inferred from observed redshifts - an estimate that is dependent on the local peculiar motion - giving a distorted view of the three dimensional structure and affecting basic observables such as the…

Astrophysics · Physics 2008-12-18 J. Richard Shaw , Antony Lewis

In effective models of loop quantum cosmology, the holonomy corrections are associated with deformations of space-time symmetries. The most evident manifestation of the deformations is the emergence of an Euclidean phase accompanying the…

General Relativity and Quantum Cosmology · Physics 2016-02-03 Susanne Schander , Aurélien Barrau , Boris Bolliet , Julien Grain , Linda Linsefors , Jakub Mielczarek

We show how, based on considerations on the observed form of the galaxy 2-point spatial correlation function xi(r), a very simplified -- yet surprisingly effective -- model for the linear density fluctuations power spectrum can be…

Astrophysics · Physics 2009-10-22 Enzo Branchini , Luigi Guzzo , Riccardo Valdarnini