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We have considered an action of the form $T+f(T)+L_m$ describing Einstein's gravity plus a function of the torsion scalar. By considering an exact power-law solution we have obtained the Friedmann equation as a differential equation for the…

General Physics · Physics 2015-05-30 M. R. Setare , F. Darabi

We investigate exact and analytic solutions in $f\left( T\right) $ gravity within the context of a Friedmann--Lema\^{\i}tre--Robertson--Walker background space with nonzero spatial curvature. For the power law theory $f\left( T\right)…

General Relativity and Quantum Cosmology · Physics 2022-01-05 Andronikos Paliathanasis

Is Newton's gravity sufficient to handle the weakly nonlinear evolution stages of the cosmic large-scale structures? Here we resolve the issue by analytically deriving the density and velocity power spectra to the second order in the…

Astrophysics · Physics 2008-11-26 Hyerim Noh , Jai-chan Hwang

We provide for the first time the growth index of linear matter fluctuations of the power law $f(T) \propto (-T)^{b}$ gravity model. We find that the asymptotic form of this particular $f(T)$ model is $\gamma \approx \frac{6}{11-6b}$ which…

General Relativity and Quantum Cosmology · Physics 2016-05-04 Spyros Basilakos

We study the evolution of density perturbations for a class of $f(R)$ models which closely mimic $\Lambda$CDM background cosmology. Using the quasi-static approximation, and the fact that these models are equivalent to scalar-tensor…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Stephen A Appleby , Jochen Weller

We present an analysis of an $f(T, \mathcal{T})$ extension of the Teleparallel Equivalent of General Relativity, where $T$ denotes the torsion and $\mathcal{T}$ the trace of the energy-momentum tensor. This extension includes non--minimal…

General Relativity and Quantum Cosmology · Physics 2016-07-27 Diego Saez-Gomez , C. Sofia Carvalho , Francisco S. N. Lobo , Ismael Tereno

We perform detailed investigation of cosmological perturbations in f(T) theory of gravity coupled with scalar field. Our work emphasizes on the way to gauge fix the theory and we examine all possible modes of perturbations up to second…

General Relativity and Quantum Cosmology · Physics 2013-06-24 Keisuke Izumi , Yen Chin Ong

We carry out a suite of cosmological simulations of modified action f(R) models where cosmic acceleration arises from an alteration of gravity instead of dark energy. These models introduce an extra scalar degree of freedom which enhances…

Astrophysics · Physics 2008-12-30 Hiroaki Oyaizu , Marcos Lima , Wayne Hu

Cosmography can be considered as a sort of a model-independent approach to tackle the dark energy/modified gravity problem. In this review, the success and the shortcomings of the $\Lambda$CDM model, based on General Relativity and standard…

General Relativity and Quantum Cosmology · Physics 2019-04-09 Salvatore Capozziello , Rocco D'Agostino , Orlando Luongo

In this paper, we have explored the field equations of f(T, B) gravity as an extension of teleparallel gravity in an isotropic and homogeneous space time. In the basic formalism developed, the dynamical parameters are derived by…

General Relativity and Quantum Cosmology · Physics 2024-09-27 S. A. Kadam , Jackson Levi Said , B. Mishra

This study offers a comprehensive reconstruction of $f(T)$ gravity model with three distinct non-linear as well as novel forms employing a hybrid scale factor to depict the expansion history of the universe starting from early decelerated…

General Relativity and Quantum Cosmology · Physics 2026-02-17 Suraj Kumar Behera , Pratik P. Ray

In this paper, we explore the model of $f(Q,T)$ gravity, an extension of symmetric teleparallel gravity where the nonmetricity scalar $Q$ is non-minimally coupled to the trace of the energy-momentum tensor $T$. To ensure general covariance…

General Relativity and Quantum Cosmology · Physics 2025-09-09 Rahul Bhagat , Santosh V. Lohakare , B. Mishra

In recent years, modifications to General Relativity (GR) have been explored to address cosmological observations, particularly in the context of late-time cosmic acceleration. Among these, modifications based on the Teleparallel Equivalent…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Saurabh Verma , Archana Dixit , Anirudh Pradhan , M. S. Barak

Within the general framework of $f(R)$ gravity, we introduce a function of the electromagnetic curvature invariant $f(\mathbb{F})$ that couples minimally to gravitation to ensure a consistent treatment of curvature functions in these…

General Relativity and Quantum Cosmology · Physics 2026-03-19 Francesco Bajardi , Micol Benetti , Salvatore Capozziello , Abedennour Dib

Noether's theory offers us a useful tool to research the conserved quantities and symmetries of the modified gravity theories, among which the $f(T)$ theory, a generally modified teleparallel gravity, has been proposed to account for the…

General Relativity and Quantum Cosmology · Physics 2013-10-07 Han Dong , Jiaxin Wang , Xinhe Meng

We investigate the cosmological predictions of several $f(T)$ models, with up to two parameters, at both the background and the perturbation levels. Using current cosmological observations (geometric supernovae type Ia, cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-17 S. Nesseris , S. Basilakos , E. N. Saridakis , L. Perivolaropoulos

In this work we study the cosmology of the general f(T) gravity theory. We express the modified Einstein equations using covariant quantities, and derive the gauge-invariant perturbation equations in covariant form. We consider a specific…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-02 Baojiu Li , Thomas P. Sotiriou , John D. Barrow

We study inflation in the framework of $f(T)$-gravity in the presence of a canonical scalar field. After reviewing the basic equations governing the background cosmology in $f(T)$-gravity, we turn to study the cosmological perturbations and…

General Relativity and Quantum Cosmology · Physics 2016-02-02 K. Rezazadeh , A. Abdolmaleki , K. Karami

This article explores the cosmological scenario of the universe in the context of the $f(T)$ power law model, where $T$ represent the torsion scalar. To obtain the deterministic solution of the field equations we parametrized the effective…

General Relativity and Quantum Cosmology · Physics 2024-11-11 S. R. Bhoyar , Yash B. Ingole

We proposed five $f(Q,T)$ models, which are an extension of symmetric teleparallel gravity, where $Q$ is the non-metricity and $T$ is the trace of the stress-energy tensor. By taking specific values of their parameters, these models have a…

General Relativity and Quantum Cosmology · Physics 2021-11-09 Antonio Nájera , Amanda Fajardo
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