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In this work we derive the covariant and gauge invariant perturbation equations in general theories of $f(R)$ gravity in the Palatini formalism to linear order and calculate the cosmic microwave background (CMB) and matter power spectra for…

Astrophysics · Physics 2008-11-26 Baojiu Li , K. C. Chan , M. -C. Chu

Cosmological perturbation theory is a powerful tool to predict the statistics of large-scale structure in the weakly non-linear regime, but even at 1-loop order it results in computationally expensive mode-coupling integrals. Here we…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-17 Xiao Fang , Jonathan A. Blazek , Joseph E. McEwen , Christopher M. Hirata

We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…

Astrophysics · Physics 2007-05-23 Carmelita Carbone , Sabino Matarrese

This study investigates the cosmological dynamics of an accelerating universe within the framework of teleparallel gravity using an exponential f(T) functional form. To obtain exact cosmological solutions, a hybrid scale factor is employed…

General Relativity and Quantum Cosmology · Physics 2026-05-27 Rajalakshmi Jena , Vishal M C , Sankarsan Tarai

The current standard cosmological model is constructed within the framework of general relativity with a cosmological constant $\Lambda$, which is often associated with dark energy, and phenomenologically explains the accelerated cosmic…

General Relativity and Quantum Cosmology · Physics 2023-06-27 Jiamin Hou , Julian Bautista , Maria Berti , Carolina Cuesta-Lazaro , César Hernández-Aguayo , Tilman Tröster , Jinglan Zheng

An efficient technique for computing perturbation power spectra in field ordering theories of cosmic structure formation is introduced, enabling computations to be carried out with unprecedented precision. Large scale simulations are used…

Astrophysics · Physics 2009-07-09 Ue-Li Pen , Uros Seljak , Neil Turok

It is a fact that the universe lives on a Gravitational Wave Background (GWB), which it may be in the form of extra energy, which is not contained in Einstein's field equations. In \cite{Matos:2021jef}, a new model was developed to explain…

General Physics · Physics 2024-04-02 Tonatiuh Matos , Luis A. Escamilla , Maribel Hernández , J. Alberto Vázquez

Ramanujan Master Theorem is a technique developed by the indian mathematician S. Ramanujan to evaluate a class of definite integrals. This technique is used here to calculate the values of integrals associated with specific Feynman…

Mathematical Physics · Physics 2011-03-04 Ivan Gonzalez , V. H. Moll , Ivan Schmidt

A detailed analysis of dynamics of cosmological models based on $R^{n}$ gravity is presented. We show that the cosmological equations can be written as a first order autonomous system and analyzed using the standard techniques of dynamical…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Carloni , P. K. S. Dunsby , S. Capozziello , A. Troisi

We present and test a framework that models the three-dimensional distribution of mass in the Universe as a function of cosmological and astrophysical parameters. Our approach combines two different techniques: a rescaling algorithm that…

Using an approach that treats the Ricci scalar itself as a degree of freedom, we analyze the cosmological evolution within an f(R) model that has been proposed recently (exponential gravity) and that can be viable for explaining the…

General Relativity and Quantum Cosmology · Physics 2012-11-02 Luisa Jaime , Marcelo Salgado , Leonardo Patino

We give a detailed and improved presentation of our recently proposed formalism for non-linear perturbations in cosmology, based on a covariant and fully non-perturbative approach. We work, in particular, with a covector combining the…

Astrophysics · Physics 2009-11-13 David Langlois , Filippo Vernizzi

General relativistic corrections to the expansion rate of the Universe arise when the Einstein equations are averaged over a spatial volume in a locally inhomogeneous cosmology. It has been suggested that they may contribute to the observed…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-01 Xinghai Zhao , Grant J. Mathews

We describe an efficient scheme for evaluating higher order contributions to primordial cosmological perturbations using the "in-in" formalism, which is the basis of modern calculations of non-Gaussian and higher order contributions to the…

High Energy Physics - Theory · Physics 2009-11-05 Peter Adshead , Richard Easther , Eugene A. Lim

We study cosmological perturbation theory in the cosmology associated with conformal gravity, establish the validity of the decomposition theorem for it, and then use the theorem to provide an exact solution to the theory in the…

General Relativity and Quantum Cosmology · Physics 2021-01-04 Philip D. Mannheim

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 next generation of cosmological surveys will operate over unprecedented scales, and will therefore provide exciting new opportunities for testing general relativity. The standard method for modelling the structures that these surveys…

General Relativity and Quantum Cosmology · Physics 2018-03-28 Sophia R. Goldberg , Christopher Gallagher , Timothy Clifton

We construct the Hamiltonian formulation of the isotropic Universe in a generic metric f(R)-theory in the Jordan frame. We canonically quantize the Universe volume via a polymer formulation, and we adopt the scalar field naturally arising…

General Relativity and Quantum Cosmology · Physics 2026-01-26 M. L. Limongi , S. Lo Franco , G. Montani , S. Segreto

Recently, inhomogeneous generalisations of the Friedmann-Lemaitre-Robertson-Walker cosmological models have gained interest in the astrophysical community and are more often employed to study cosmological phenomena. However, in many papers…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-17 Krzysztof Bolejko , Marie-Noëlle Célérier , Andrzej Krasiński

We present a Mathematica package for performing algebraic and numerical computations in cosmological models based on supersymmetric theories. The programs allow for (I) evaluation and study of the properties of a scalar potential in a large…

High Energy Physics - Theory · Physics 2007-05-23 Renata Kallosh , Sergey Prokushkin
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