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We develop the reconstruction program for the number of modified gravities: scalar-tensor theory, $f(R)$, $F(G)$ and string-inspired, scalar-Gauss-Bonnet gravity. The known (classical) universe expansion history is used for the explicit and…

High Energy Physics - Theory · Physics 2010-04-06 Shin'ichi Nojiri , Sergei D. Odintsov

The current paper reports an investigation of the cosmological implications of symmetric teleparallel gravity within a modified $f(Q)$ theory. We construct a specific exponential $f(Q)$ model as $f(Q) = Q + \eta_1 Q_0\left(1 - e^{-\eta_2…

General Relativity and Quantum Cosmology · Physics 2025-11-11 Sanjeeda Sultanaa , Surajit Chattopadhyay

An accelerated expansion phase is being experienced by the universe due to the presence of an unknown energy component known as dark energy (DE). To find out the cosmic evolution scientists ever tried to modify Einstein's gravitational…

General Physics · Physics 2018-11-14 M. Zubair , M. Zeeshan

Motivated by the fact that cosmological models based on $f(Q)$ gravity are very efficient in fitting observational datasets at both background and perturbation levels, we perform a combined dynamical system analysis of both background and…

General Relativity and Quantum Cosmology · Physics 2023-02-22 Wompherdeiki Khyllep , Jibitesh Dutta , Emmanuel N. Saridakis , Kuralay Yesmakhanova

Modified theories of gravity encompass a class of $f(R)$-models that seek to elucidate the observed late time accelerated expansion of the universe. In this study, we examine a set of viable $f(R)$ models (Hu-Sawicki: two cases,…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-15 Kumar Ravi , Anirban Chatterjee , Biswajit Jana , Abhijit Bandyopadhyay

We perform a phase space analysis of a non-minimally coupled modified gravity theory with the Lagrangian density of the form $\frac{1}{2} f_{1}(R)+[1+\lambda f_{2}(R)]{{\cal{L}}_{m}}$, where $f_1(R)$ and $f_2(R)$ are arbitrary functions of…

General Relativity and Quantum Cosmology · Physics 2014-06-03 Tahereh Azizi , Emad Yaraie

The study conducted in this research paper utilizes the $f(Q,T)$ gravity, where $Q$ represents non-metricity and $T$ represents the trace of the energy-momentum tensor, to investigate the accelerated expansion of the universe. To complete…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-17 M. Koussour , N. Myrzakulov , J. Rayimbaev , A. Errehymy , Orhan Donmez

This thesis investigates the characteristics of modified teleparallel gravity models that incorporate a scalar field and a trace of the energy-momentum tensor, with particular attention to their cosmological effects, especially regarding…

General Relativity and Quantum Cosmology · Physics 2025-10-06 L K Duchaniya

In this paper, we investigate the exact solution of an anisotropic space-time in the context of $f(Q)$ gravity, where $f\left( Q\right) $ is the arbitrary function of the non-metricity scalar $Q$. Here, we consider a specific power-law form…

General Relativity and Quantum Cosmology · Physics 2022-12-01 M. Koussour , M. Bennai

The $f(Q,C)$ framework of gravity enables the depiction of an effective dark energy fluid that emerges from geometry itself, thus leading to modifications in the cosmological phenomenology of General Relativity. We pursue this approach to…

General Relativity and Quantum Cosmology · Physics 2025-12-01 Mikel Artola , Ismael Ayuso , Ruth Lazkoz , Gonzalo Olmo , Vincenzo Salzano

We investigate the impact on cosmological observables of $f(Q)$-gravity, a specific class of modified gravity models in which gravity is described by the non-metricity scalar, $Q$. In particular we focus on a specific model which is…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-24 Noemi Frusciante

The discovery of cosmic acceleration has raised the intriguing possibility that we are witnessing the first breakdown of General Relativity on cosmological scales. In this article I will briefly review current attempts to construct a…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Mark Trodden

We investigate some FLRW cosmological models in the context of Metric-Affine $F(R,Q)$ gravity, as proposed in [arXiv:1205.52666]. Here, $R$ and $Q$ are the curvature and nonmetricity scalars using non-special connections, respectively. We…

General Relativity and Quantum Cosmology · Physics 2024-08-16 Dinesh Chandra Maurya , K. Yesmakhanova , R. Myrzakulov , G. Nugmanova

I review a class of nonlocally modified gravity models which were proposed to explain the current phase of cosmic acceleration without dark energy. Among the topics considered are deriving causal and conserved field equations, adjusting the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 R. P. Woodard

In this paper, we have studied the late-time accelerating expansion of the Universe using the matter-geometry coupled $ f(Q, T) $ gravity model, where $ Q $ is the non-metricity scalar and $ T $ represents the trace of the energy-momentum…

General Relativity and Quantum Cosmology · Physics 2025-03-03 Shambel Sahlu , Bhupendra Kumar Shukla , Rishi Kumar Tiwari , Değer Sofuoğlu , Alnadhief H. A. Alfedeel

We present a novel theory of gravity by considering an extension of symmetric teleparallel gravity. This is done by introducing, in the framework of the metric-affine formalism, a new class of theories where the nonmetricity $Q$ is…

General Relativity and Quantum Cosmology · Physics 2018-10-31 Tiberiu Harko , Tomi S. Koivisto , Francisco S. N. Lobo , Gonzalo J. Olmo , Diego Rubiera-Garcia

In this paper, a cosmological model of the Universe is presented in $f(Q,T)$ gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of $f(Q,T)$ model is used as $f(Q,T)=-\lambda_{1}…

General Relativity and Quantum Cosmology · Physics 2024-03-21 A. S. Agrawal , B. Mishra , S. K. Tripathy

I briefly discuss some attempts to construct a consistent modification to General Relativity (GR) that might explain the observed late-time acceleration of the universe and provide an alternative to dark energy. I mention the issues facing…

Astrophysics · Physics 2008-11-26 Mark Trodden

In this paper, the dynamical behavior of the accelerated expansion of the universe is discussed within the framework of $f(T)$ gravity, considering power law functional form of $ f(T)=\alpha (-T)^{n}$. Two distinct redshift-dependent…

General Relativity and Quantum Cosmology · Physics 2025-08-29 Shivank Pal , Romanshu Garg , Gyan Prakash Singh , Gauree Shanker

We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of General Relativity (GR) has been tested accurately…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-24 Kazuya Koyama
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