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Related papers: Implementing F (T ) Gravity in Boltzmann Codes: A …

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We present a formalism to calculate the non-linear matter power spectrum in modified gravity models that explain the late-time acceleration of the Universe without dark energy. Any successful modified gravity models should contain a…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-03 Kazuya Koyama , Atsushi Taruya , Takashi Hiramatsu

Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Mahmoud Hashim , Amr A. El-Zant , Waleed El Hanafy , Alexey Golovnev

In this paper, we study the non-linear matter power spectrum in a specific family of $f(R)$ models that can reproduce the $\Lambda$CDM background expansion history, using high resolution $N$-body simulations based on the {\sc ecosmog} code.…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-13 Jian-hua He , Baojiu Li , Yipeng Jing

We study in detail how neutrino perturbations can be followed in linear theory by using only terms up to $l=2$ in the Boltzmann hierarchy. We provide a new approximation to the third moment and demonstrate that the neutrino power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-15 Maria Archidiacono , Steen Hannestad

In this work, we consider three different $f(Q)$ models, such as power-law, exponential, and logarithmic, to study which model better mimics $\Lambda$CDM evolution theoretically. Henceforth, we determine solutions to the $f(Q)$ gravity…

General Relativity and Quantum Cosmology · Physics 2024-05-10 Gaurav N. Gadbail , P. K. Sahoo

Many modified gravity theories are under consideration in cosmology as the source of the accelerated expansion of the universe and linear perturbation theory, valid on the largest scales, has been examined in many of these models. However,…

General Relativity and Quantum Cosmology · Physics 2015-11-06 Daniel B Thomas , Marco Bruni , Kazuya Koyama , Baojiu Li , Gong-Bo Zhao

In this paper, we study the nonlinear electrodynamics in the framework of $f(T)$ gravity for FRW universe along with dust matter, magnetic and torsion contributions. We evaluate the equation of state and deceleration parameters to explore…

General Relativity and Quantum Cosmology · Physics 2015-06-19 M. Sharif , Shamaila Rani

We investigate two new observational perspectives in the context of torsional gravitational modification of general relativity, i.e., the $f(T)$ gravity: i) We use Pantheon data of type Ia supernovae motivated by a time variation of the…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-21 Suresh Kumar , Rafael C. Nunes , Priya Yadav

The expansion of the Universe in $f(R,T)$ gravity is studied. We consider functions of the form $f(R,T)=R+\lambda T^\epsilon$ where $\epsilon<1$. We find that for all models with $\epsilon<0$, the Universe transitions to exponential growth…

General Relativity and Quantum Cosmology · Physics 2026-03-26 Vincent R. Siggia , Eric D. Carlson , P. Lee Pryor

We compare Einstein-Boltzmann solvers that include modifications to General Relativity and find that, for a wide range of models and parameters, they agree to a high level of precision. We look at three general purpose codes that primarily…

Recent work in the literature has found a suppression or, instead, an enhancement of the Cosmic Microwave Background power spectrum in quantum gravity, although the effect is too small to be observed, in both cases. The present paper…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Donato Bini , Giampiero Esposito

$f(R,T)$ gravity is a widely used extended theory of gravity introduced in \cite{9} which is a straightforward generalization of $f(R)$ gravity. The action in this extended theory of gravity incorporates well motivated functional forms of…

General Relativity and Quantum Cosmology · Physics 2020-07-09 Snehasish Bhattacharjee , P. K. Sahoo

We investigate f(R) theories of gravity within the Palatini approach and show how one can determine the expansion history, H(a), for an arbitrary choice of f(R). As an example, we consider cosmological constraints on such theories arising…

Astrophysics · Physics 2008-11-26 M. Amarzguioui , O. Elgaroy , D. F. Mota , T. Multamaki

Power-law corrections (having the exponent strictly between 2 and 3) to the Einstein-Hilbert action yield an extended theory of gravity which is consistent with Solar-System tests and properly reproduces the main phases of the Universe…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-13 Salvatore Capozziello , Nakia Carlevaro , Mariafelicia De Laurentis , Massimiliano Lattanzi , Giovanni Montani

The $f(T)$ theory, which is an extension of teleparallel, or torsion scalar $T$, gravity, is recently proposed to explain the present cosmic accelerating expansion with no need of dark energy. In this Letter, we first perform the…

General Relativity and Quantum Cosmology · Physics 2010-10-12 Puxun Wu , Hongwei Yu

We study the cosmology of a specific class of nonlocal model of modified gravity, the so-called Deser-Woodard (DW) model, modifying the Einstein-Hilbert action by a term $\sim R f(\Box^{-1}R)$, where $f$ is a free function. Choosing $f$ so…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-18 Luca Amendola , Yves Dirian , Henrik Nersisyan , Sohyun Park

We present a new open-source code that calculates one-loop power auto- and cross-power spectra for matter fields and biased tracers in real and redshift space. These spectra incorporate all ingredients required for a direct application to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Anton Chudaykin , Mikhail M. Ivanov , Oliver H. E. Philcox , Marko Simonović

We propose and construct a two-parameter perturbative expansion around a Friedmann-Lema\^{i}tre-Robertson-Walker geometry that can be used to model high-order gravitational effects in the presence of non-linear structure. This framework…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Sophia R. Goldberg , Timothy Clifton , Karim A. Malik

We study the growth of cosmological perturbations in the model of Lorentz-violating massive gravity. The Friedman equation in this model acquires an unconventional term due to the Lorentz-breaking condensates which has the equation of state…

Astrophysics · Physics 2008-12-18 Michael V. Bebronne , Peter G. Tinyakov

We investigate the cosmological solutions of the $f(T)$ gravity theory using the method of dynamical systems. For this purpose a general form of the $f(T)$ function is considered and four conditions are defined that they have to satisfy in…

General Relativity and Quantum Cosmology · Physics 2017-12-12 Behrouz Mirza , Fatemeh Oboudiat