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In the context of the Relativistic Quantum Geometry formalism, where the cosmological constant is promoted to a dynamical variable by attributing it a geometric interpretation as a result of a flux on the boundary of a manifold and…

General Relativity and Quantum Cosmology · Physics 2025-04-15 Juan Ignacio Musmarra , Claudia Moreno , Rafael Hernández-Jiménez

Assuming a spatially flat universe, we study the cosmological viability of an infrared corrected teleparallel gravity model, which accounts for late acceleration by weakening gravity at later times on cosmological distances. The theory does…

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

The main objective of this article is to investigate the viability of bouncing cosmological scenarios using different forms of scale factors with perfect matter configuration in the framework of extended symmetric teleparallel theory. This…

General Relativity and Quantum Cosmology · Physics 2024-07-31 M. Zeeshan Gul , M. Sharif , Shamraiza Shabbir

We explore the possibility of realizing a non-singular bounce in the early universe within the framework of modified gravity with spacetime torsion. In Einstein Cartan theory, torsion is embedded in the spacetime by adding an antisymmetric…

General Relativity and Quantum Cosmology · Physics 2026-01-21 Sonej Alam , Somasri Sen , Soumitra Sengupta

Over the last decades, tests on the standard model of cosmology, the so-called $\Lambda$CDM model, have been widely analysed and compared with many different models for describing dark energy. Modified gravities have played an important…

General Relativity and Quantum Cosmology · Physics 2024-12-13 Sergei D. Odintsov , Diego Sáez-Chillón Gómez , German S. Sharov

We show that the f(T) gravitational paradigm, in which gravity is described by an arbitrary function of the torsion scalar, can provide a mechanism for realizing bouncing cosmologies, thereby avoiding the Big Bang singularity. After…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-07 Yi-Fu Cai , Shih-Hung Chen , James B. Dent , Sourish Dutta , Emmanuel N. Saridakis

The paper presents late time cosmology in $f(Q,T)$ gravity where the dark energy is purely geometric in nature. We start by employing a well motivated $f(Q,T)$ gravity model, $f(Q,T)=mQ^{n}+bT$ where $m,n$ and $b$ are model parameters.…

General Relativity and Quantum Cosmology · Physics 2020-07-06 Simran Arora , S. K. J. Pacif , Snehasish Bhattacharjee , P. K. Sahoo

We consider the symmetric teleparallel $f\left( Q\right) $-gravity in Friedmann--Lema\^{\i}tre--Robertson--Walker cosmology with nonzero spatial curvature. For a nonlinear $f\left( Q\right) $ model there exist always the limit of General\…

General Relativity and Quantum Cosmology · Physics 2023-10-09 Andronikos Paliathanasis

We consider tensor-vector theories with varying the space-time-matter coupling constant (varying Einstein velocity) in a spatially flat FRW universe. We examine the dynamics of this model by dynamical system method assuming a \Lambda CDM…

General Physics · Physics 2015-06-11 Azam Izadi , Ali Shojai , Mojtaba Nouradini

Here we analysed a particular type of $F(R)$ gravity, the so-called exponential gravity which includes an exponential function of the Ricci scalar in the action. Such term represents a correction to the usual Hilbert-Einstein action. By…

General Relativity and Quantum Cosmology · Physics 2018-01-17 Sergei D. Odintsov , Diego Saez-Chillon Gomez , German S. Sharov

The current transit universe model is a precise solution to the equations of a new type of gravity theory called metric-affine $f(R,T,Q,T_m)$ gravity proposed in [Herko et al. \textit{Phys. Dark Univ.} \textbf{34} (2021) 100886]. This…

General Relativity and Quantum Cosmology · Physics 2026-02-19 Dinesh Chandra Maurya , Harjit Kumar

The quantum field theoretic prediction for the vacuum energy density leads to a value for the effective cosmological constant that is incorrect by between 60 to 120 orders of magnitude. We review an old proposal of replacing Einstein's…

General Relativity and Quantum Cosmology · Physics 2011-10-24 George F. R. Ellis , Henk van Elst , Jeff Murugan , Jean-Philippe Uzan

In this paper, we discuss the Bianchi type-I cosmological model in the framework of symmetric teleparallel gravity say $f(Q)$ gravity in which the non-metricity term $Q$ is responsible for the gravitational interaction. We consider a…

General Relativity and Quantum Cosmology · Physics 2023-04-05 M. Koussour , S. H. Shekh , M. Govender , M. Bennai

The discovery of the accelerated expansion of the universe highlighted General Relativity's inability to naturally account for dark energy without invoking a finely tuned cosmological constant. In response, a wide range of alternative…

General Relativity and Quantum Cosmology · Physics 2025-11-11 P. A. G. Monteiro , C. J. A. P. Martins

We generalize our previous theorem for FLRW spacetimes within the framework of generic metric gravity theories. In earlier work, we proved that, in the absence of matter fields, the field equations of any metric gravity theory constructed…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Metin Gürses , Yaghoub Heydarzade

We investigate the cosmological viability of symmetric teleparallel gravity, specifically the $f(Q)$ gravity model with a power-law form $f(Q) = \alpha Q^n$, in combination with two widely used dark energy parameterizations: Chevallier…

General Relativity and Quantum Cosmology · Physics 2025-07-09 Rajdeep Mazumdar , Mrinnoy M. Gohain , Kalyan Bhuyan

A new class of modified gravity theories with a healthy higher order derivative terms of a function of the matter Lagrangian $f(L_m)$ is considered. Generally the energy momentum tensor is not conserved, leading to the fifth force similar…

General Relativity and Quantum Cosmology · Physics 2021-04-19 Zahra Haghani , Shahab Shahidi

In this dissertation, we study two cosmological models based on $f(Q)$ gravity. We resort to mock catalogs of standard siren (SS) events to see whether data from future gravitational wave (GWs) observatories will be able to distinguish…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-23 José Ferreira

In this work, we examine viable models of $f(Q,T)$ gravity theories against observational data with the aim to constrain the parameter space of these models. We have analysed five different models of $f(Q,T)$ gravity and tested them against…

General Relativity and Quantum Cosmology · Physics 2024-08-28 Shreya Banerjee , Aritrya Paul

Modified $f(R)$ gravity in the Palatini approach has been presently applied to Cosmology as a realistic alternative to dark energy. In this concern, a number of authors have searched for observational constraints on several $f(R)$ gravity…

Astrophysics · Physics 2009-06-23 F. C. Carvalho , E. M. Santos , J. S. Alcaniz , J. Santos