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This thesis investigates late-time cosmic acceleration using modified gravity theories with a focus on $f(Q)$ gravity, as an alternative to the $\Lambda$CDM model. The standard cosmological model attributes the acceleration to a…

General Relativity and Quantum Cosmology · Physics 2025-12-18 S. A. Narawade

We investigate the exponential $f(Q)$ symmetric teleparallel gravitation, namely $f(Q)=Q+\alpha Q_0(1-e^{-\beta\sqrt{Q/Q_0}})$ using \texttt{ME-GADGET} code to probe the structure formation with box sizes $L_{\mathrm{box}}=10/100$ Mpc$/h$…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-18 Oleksii Sokoliuk , Simran Arora , Subhrat Praharaj , Alexander Baransky , P. K. Sahoo

This paper explores the dark energy phenomenon within the context of $f(R,L_m)$ gravity theory. Two specific non-linear $f (R, L_m)$ models are considered: $f(R,L_m)=\frac{R}{2}+L_m^\alpha$ and $f(R,L_m)=\frac{R}{2}+(1+\alpha R)L_m$, where…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-13 S. Myrzakulova , M. Koussour , N. Myrzakulov

In this article, we have investigated the role of bulk viscosity to study the accelerated expansion of the universe in the framework of modified $f(Q)$ gravity. The gravitational action in this modified gravity theory has the form $f(Q)$,…

General Relativity and Quantum Cosmology · Physics 2022-07-20 Raja Solanki , S. K. J. Pacif , Abhishek Parida , P. K. Sahoo

We propose a new parametrization of the deceleration parameter to study its time-variation behavior. The advantage of parameterizing the deceleration parameter is that we do not need to assume any underlying theory of gravity. By fitting…

Astrophysics · Physics 2008-11-26 Yungui Gong , Anzhong Wang

We study a minimal modified gravity scenario in the symmetric teleparallel (non-metricity) formulation, focusing on an inverse non-metricity term with $f(Q)=Q+M^4 Q^{-1}$. The model does not introduce additional free parameters relative to…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-31 Luís Atayde , Simão Marques Nunes , Noemi Frusciante

In this work, we study the f(Q,T) model of symmetric teleparallel modified gravity in the framework of cosmological perturbation theory. Using a general approach, we extract the differential matter density equation then we simplify it as a…

General Relativity and Quantum Cosmology · Physics 2025-08-06 Houda Filali , Rachid Ahl Laamara , Mohamed Bennai , El Hassan Saidi

In the present analysis, we explore a new version of dark energy called Barrow holographic dark energy within the framework modified gravity called $f(Q,T)$ gravity by adopting the simple homogeneous, isotropic, and spatially flat…

General Relativity and Quantum Cosmology · Physics 2024-08-09 N. Myrzakulov , S. H. Shekh , Anirudh Pradhan , K Ghaderi

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

In this paper, we considered the study of Friedmann-Robertson-Walker (FRW) model in the framework of $f(Q,T)$ gravity, an extension of symmetric teleparallel gravity, recently defined by Y. Xu et al. \cite{Xu}. The non-linear model…

General Relativity and Quantum Cosmology · Physics 2021-05-05 Nisha Godani , Gauranga C Samanta

We propose a specialized parameterization for the Hubble parameter, inspired by $\Lambda$CDM cosmology, to investigate the cosmic expansion history of the Universe. This parameterization is employed to analyze the Universe's late-time…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-23 M. Koussour , N. Myrzakulov

In this work, we explore the cosmological dynamics of a modified gravity framework based on the function $f(Q,B)=\delta Q^{2}+\beta B$, where $Q$ denotes the nonmetricity scalar and $B$ is the boundary term that relates $Q$ to the Ricci…

General Relativity and Quantum Cosmology · Physics 2025-07-22 Amit Samaddar , S. Surendra Singh

We reexamine the kink-like parameterization of the deceleration parameter to derive constraints on the transition redshift from cosmic deceleration to acceleration. This is achieved using observational Hubble data, Type Ia Supernovae…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-30 Simran Arora , P. K. Sahoo

In this paper, we investigate the effects of varying bulk viscosity coefficients $\zeta(t)=\zeta_{0}+\zeta_{1}H$ on cosmic evolution within the framework of $f(T)$ teleparallel gravity. We focus on two cases: (i) $\zeta_{1} \neq0$ and (ii)…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Kairat Myrzakulov , O. Donmez , M. Koussour , S. Muminov , E. Davletov , J. Rayimbaev

In this paper, we investigate the existence of bulk viscous FLRW cosmological models in a recently proposed extended symmetric teleparallel gravity or $f\left( Q,T\right) $ gravity in which $Q$ is the non-metricity and $T$ is the trace of…

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

The parametrizations $q=q_0+q_1 z$ and $q=q_0+q_1 (1-a/a_0)$ (Chevallier-Polarski-Linder parametrization) of deceleration parameter, which are linear in cosmic redshift $z$ and scale factor $a$, have been frequently utilized in the…

General Relativity and Quantum Cosmology · Physics 2014-02-05 Ozgur Akarsu , Tekin Dereli , Suresh Kumar , Lixin Xu

In the last century, theoretical and experimental developments have established the General Relativity theory as the most successful theory for describing the gravitational phenomenon. On the other hand, in the last two decades, multiple…

General Relativity and Quantum Cosmology · Physics 2025-02-18 Raja Solanki

In this paper, we study three models of f(R) modified gravity including higher order terms based on different equation of state parameter. We also assume variable G and $\Lambda$. By using numerical analysis, we obtain the behavior of some…

General Relativity and Quantum Cosmology · Physics 2015-04-07 M. Khurshudyan , B. Pourhassan , A. Pasqua

Within the framework of modified teleparallel gravity, we reconstruct a f(T) model corresponding to the QCD ghost dark energy scenario. For a spatially flat FRW universe containing only the pressureless matter, we obtain the time evolution…

General Physics · Physics 2014-01-30 K. Karami , A. Abdolmaleki , S. Asadzadeh , Z. Safari

Using the cosmological date sets, the cosmological parameters are constrained in this paper, with some well known form of Hubble parameter. To understand the dynamics of the Weyl type $f(Q,T)$, functional form $f(Q,T)$ has been introduced,…

General Relativity and Quantum Cosmology · Physics 2024-09-05 Rahul Bhagat , B. Mishra
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