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We investigate the influence of bulk viscosity on late-time cosmic acceleration within an extended $f(Q, L_m)$ gravity framework, where the non-metricity $Q$ is non-minimally coupled with the matter Lagrangian $L_m$. Analyzing the function…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Y. Myrzakulov , O. Donmez , M. Koussour , S. Muminov , I. Y. Davletov , J. Rayimbaev

We study the evolution of a flat Friedmann-Robertson- Walker Universe, filled with a bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The dimensional analysis of the model suggest a…

General Relativity and Quantum Cosmology · Physics 2009-09-25 J. A. Belinchon , T. Harko , M. K. Mak

In this paper, we find several teleparallel $F(T,B)$ solutions for a Robertson--Walker (TRW) cosmological spacetime. We first set and solve the $F(T,B)$-type field equations for a linear perfect fluid. Using similar techniques, we then find…

General Relativity and Quantum Cosmology · Physics 2025-01-22 Fateme Gholami , Alexandre Landry

This paper examines the late-time accelerating Universe and the formation of large-scale structures within the modified symmetric teleparallel gravity framework, specifically using the $f(Q)$-gravity model, in light of recent cosmological…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Shambel Sahlu , Amare Abebe

In Einstein's General Relativity (GR), the gravitational interactions are described by the spacetime curvature. Recently, other alternative geometric formulations and representations of GR have emerged in which the gravitational…

General Relativity and Quantum Cosmology · Physics 2023-08-16 A. Hanin , M. Koussour , Z. Sakhi , M. Bennai

In this paper, we construct an isotropic cosmological model in the $ f(Q, T) $ theory of gravity in the frame of a flat FLRW spacetime being $ Q $ the non-metricity tensor and $ T $ the trace of the energy-momentum tensor. The gravity…

General Relativity and Quantum Cosmology · Physics 2025-04-24 Akanksha Singh , Shaily , J. K. Singh , Ertan Güdekli

There are so many ideas that potentially explain the dark energy phenomenon, current research is focusing on a more in-depth analysis of the potential effects of modified gravity on both local and cosmic scales. In this paper we have…

General Relativity and Quantum Cosmology · Physics 2025-11-24 S. H. Shekh , Hira Sohail , Irfan Mahmood , Allah Ditta , Anil Kumar Yadav

$f(Q,T)$ gravity is a novel extension of the symmetric teleparallel gravity where the Lagrangian $L$ is represented through an arbitrary function of the nonmetricity $Q$ and the trace of the energy-momentum tensor $T$ \cite{fqt}. In this…

General Relativity and Quantum Cosmology · Physics 2022-03-23 Snehasish Bhattacharjee

$f(T,B)$ teleparallel gravity is a recently proposed straightforward generalization of the popular $f(T)$ teleparallel gravity by the incorporation of a boundary term $B=\frac{2}{e}\partial_{i}(e T ^{i}) = \bigtriangledown_{i}T^{i}$ where…

General Relativity and Quantum Cosmology · Physics 2020-08-25 Snehasish Bhattacharjee

In this letter, we investigate the cosmic expansion scenario of the universe in the framework of $f(R,L_m)$ gravity theory. We consider a non-linear $f(R,L_m)$ model, specifically, $f(R,L_m)=\frac{R}{2}+L_m^n + \beta$, where $n$ and $\beta$…

General Relativity and Quantum Cosmology · Physics 2023-11-02 Lakhan V. Jaybhaye , Raja Solanki , Sanjay Mandal , P. K. Sahoo

We discuss a modified form of gravity implying that the action contains a power \alpha of the scalar curvature. Coupling with the cosmic fluid is assumed. As equation of state for the fluid, we take the simplest version where the pressure…

General Relativity and Quantum Cosmology · Physics 2009-11-11 I. Brevik , O. Gorbunova , Y. A. Shaido

This cosmological model is a study of modified $f(Q,T)$ theory of gravity which was recently proposed by Xu {\it et al.} (Eur. Phys. J. C {\bf 79}, 708 (2019)). In this theory of gravity, the action contains an arbitrary function $f(Q,T)$…

General Physics · Physics 2021-09-03 Anirudh Pradhan , Archana Dixit

The problem of cosmic acceleration and dark energy is one of the mysteries presently posed in the scientific society that general relativity has not been able to solve. In this work, we have considered alternative models to explain this…

General Relativity and Quantum Cosmology · Physics 2022-12-01 M. Koussour , N. Myrzakulov , S. H. Shekh , M. Bennai

We developed the cosmological linear theory of perturbations for $f(Q,T)$ gravity, which is an extension of symmetric teleparallel gravity, with $Q$ the non-metricity and $T$ the trace of the stress-energy tensor. By considering an ansatz…

General Relativity and Quantum Cosmology · Physics 2022-03-11 Antonio Nájera , Amanda Fajardo

In this paper, we investigate the cosmological implications and constraints of Weyl-type $f(Q, T)$ gravity. This theory introduces a coupling between the non-metricity $Q$ and the trace $T$ of the energy-momentum tensor, using the…

General Relativity and Quantum Cosmology · Physics 2024-03-27 Alnadhief H. A. Alfedeel , M. Koussour , N. Myrzakulov

In this paper, we have investigated the late time cosmic acceleration issue in the context of $f(R,T)$ gravity. The matter field is considered to be that of viscous fluid. The model has been framed as a mathematical formalism and the effect…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Sankarsan Tarai , Pratik P Ray , B. Mishra , S. K. Tripathy

We consider generalized teleparallel gravity in the flat FRW universe with a viable power-law f(T) model. We construct its equation of state and deceleration parameters which give accelerated expansion of the universe in quintessence era…

General Physics · Physics 2015-06-18 M. Sharif , Shamaila Rani

In this paper, we have studied the dynamical aspects of the cosmological model of the Universe in the Weyl type $f(Q,T)$ gravity, which is an extension of symmetric teleparallel gravity. The non-metricity scalar $Q$ has been expressed in…

General Relativity and Quantum Cosmology · Physics 2023-06-02 Rahul Bhagat , S. A. Narawade , B. Mishra

The authors considered the bulk viscous fluid in $f(R, T)$ gravity within the framework of Kaluza-Klein space time. The bulk viscous coefficient $(\xi)$ expressed as $\xi=\xi_0+\xi_1\frac{\dot{a}}{a}+\xi_2\frac{\ddot{a}}{\dot{a}}$, where…

General Relativity and Quantum Cosmology · Physics 2017-04-26 G. C. Samanta , R. Myrzakulov , Parth Shah

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