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We investigate the evolution of linear perturbations in the Symmetric Teleparallel Gravity, namely $f(Q)$ gravity, for which we design the $f(Q)$ function to match specific expansion histories. We consider different evolutions of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-10 Inês S. Albuquerque , Noemi Frusciante

We propose an extension of the symmetric teleparallel gravity, in which the gravitational action $L$ is given by an arbitrary function $f$ of the nonmetricity $Q$ and of the trace of the matter energy-momentum tensor $T$, so that…

General Relativity and Quantum Cosmology · Physics 2020-05-19 Yixin Xu , Guangjie Li , Tiberiu Harko , Shi-Dong Liang

We illustrate a general reconstruction procedure for mimetic gravity. Focusing on a bouncing cosmological background, we derive general properties that must be satisfied by the function $f(\Box\phi)$ implementing the limiting curvature…

General Relativity and Quantum Cosmology · Physics 2019-05-10 Marco de Cesare

As one of the possible extensions of Einstein's General Theory of Relativity, it has been recently suggested that the presence of spacetime torsion could solve problems of the very early and the late-time universe undergoing accelerating…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-19 Tonghua Liu , Ziqiang Liu , Jiamin Wang , Shengnan Gong , Man Li , Shuo Cao

In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $\Lambda$(t) within the spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) framework. Here we study a power-law $\Lambda(t)$CDM model…

General Relativity and Quantum Cosmology · Physics 2025-10-28 Archana Dixit , Manish Yadav , Anirudh Pradhan , M. S. Barak

We explore an extension of the symmetric teleparallel gravity denoted the $f(Q)$ theory, by considering a function of the nonmetricity invariant $Q$ as the gravitational Lagrangian. Some interesting properties could be found in the $f(Q)$…

General Relativity and Quantum Cosmology · Physics 2019-06-24 Jianbo Lu , Xin Zhao , Guoying Chee

We study the dynamics of homogeneous and isotropic Friedmann-Lema\^itre-Robertson-Walker cosmological models with positive spatial curvature within the context of mimetic gravity theory by employing dynamical system techniques. Our analysis…

General Relativity and Quantum Cosmology · Physics 2024-09-18 Alberto Fritis , Daniel Villalobos-Silva , Yerko Vásquez , Carlos H. López-Caraballo , Juan Carlos Helo

We develop a simple method of dark energy reconstruction using a geometrical form of the luminosity-distance relation. In this method the FRW dynamical system with dark energy is reconstructed instead of the equation of state parameter. We…

Astrophysics · Physics 2017-09-29 Marek Szydlowski , Aleksandra Kurek

An exact cosmological solution of Einstein field equations (EFEs) is derived for a dynamical vacuum energy in $f(R,T)$ gravity for Friedmann-Lemaitre-Robertson-Walker (FLRW) space-time. A parametrization of the Hubble parameter is used to…

General Physics · Physics 2018-11-22 Ritika Nagpal , S. K. J. Pacif , J. K. Singh , Kazuharu Bamba , A. Beesham

In this paper, a modified factor $\mu$, which characterizes modified gravity in the linear matter density perturbation theory, is reconstructed in a data-driven and almost model-independent way via Gaussian process by using currently…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-12 Yuhao Mu , En-Kun Li , Lixin Xu

We study the phenomenology of a class of minimally modified gravity theories called $f(\mathcal{H})$ theories, in which the usual general relativistic Hamiltonian constraint is replaced by a free function of it. After reviewing the…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-11 Katsuki Aoki , Antonio De Felice , Shinji Mukohyama , Karim Noui , Michele Oliosi , Masroor C. Pookkillath

In this article, we present a generic dynamical system formulation for Bianchi-I cosmology in the presence of an isotropic fluid within the coincident gauge connection branch and one of the non-coincident gauge connection branches of $f(Q)$…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Ghulam Murtaza , Saikat Chakraborty , Avik De

In this work, we apply the smooth deformation concept in order to obtain a modification of Friedmann equations. It is shown that the cosmic coincidence can be at least alleviated using the dynamical properties of the extrinsic curvature. We…

General Relativity and Quantum Cosmology · Physics 2017-04-06 A. J. S Capistrano , L. A. Cabral

In the past few years, $f(Q)$ theories have drawn a lot of research attention in replacing Einstein's theory of gravity successfully. The current study examines the novel cosmological possibilities emerging from two specific classes of…

General Relativity and Quantum Cosmology · Physics 2023-05-31 M. Koussour , Avik De

We reconstruct the cosmological background evolution under the scenario of dynamical dark energy through the Gaussian process approach, using the latest Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillations (BAO) combined…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-02 Yuhang Yang , Xin Ren , Qingqing Wang , Zhiyu Lu , Dongdong Zhang , Yi-Fu Cai , Emmanuel N. Saridakis

We take into account redshift-space distortion measurements to investigate the growth of cosmological large-scale structures within the framework of modified symmetric teleparallel $f(Q)$ gravity. After comparing the predictions of the…

General Relativity and Quantum Cosmology · Physics 2025-03-20 Shambel Sahlu , Álvaro de la Cruz-Dombriz , Amare Abebe

We consider a generic cosmological model which allows for non-gravitational direct couplings between dark matter and dark energy. The distinguishing cosmological features of these couplings can be probed by current cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Carsten van de Bruck , Jurgen Mifsud

Motivated by the newly proposal for gravity as the effect of the torsion scalar $T$ and trace of the energy momentum tensor $\mathcal{T}$,we investigate the cosmological reconstruction of different models of the Universe. Our aim here is to…

General Relativity and Quantum Cosmology · Physics 2018-10-09 Davood Momeni , Ratbay Myrzakulov

In this work, we reconstruct the Hubble diagram using various data sets, including correlated ones, in Artificial Neural Networks (ANN). Using ReFANN, that was built for data sets with independent uncertainties, we expand it to include…

General Relativity and Quantum Cosmology · Physics 2023-11-01 Konstantinos F. Dialektopoulos , Purba Mukherjee , Jackson Levi Said , Jurgen Mifsud

Using the mathematical definitions of deceleration and jerk parameters we obtain a general differential equation for squared Hubble parameter. For a constant jerk, this differential equation leads to an exact function for Hubble parameter.…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-21 Hassan Amirhashchi , Soroush Amirhashchi