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We propose a revised formulation of General Relativity for cosmological settings, in which the Einstein constant varies with the energy density of the Universe. We demonstrate that this modification has only phenomenological impact of…

General Relativity and Quantum Cosmology · Physics 2025-08-28 Giovanni Montani , Giulia Maniccia , Elisa Fazzari , Alessandro Melchiorri

In this work, we study a cosmological model of spatially homogeneous and isotropic accelerating universe which exhibits a transition from deceleration to acceleration. For this, Friedmann Robertson Walker(FRW) metric is taken and Hybrid…

General Relativity and Quantum Cosmology · Physics 2021-08-02 G. K. Goswami , Anirudh Pradhan , Meena Mishra , A. Beesham

In this paper, we have studied an interacting dark energy model. We have assumed the gravitational interaction between the matter fields i.e. between barotropic fluid and the dark energy. The dark energy evolution within the framework of…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Keshav Ram Mishra , Shibesh Kumar Jas Pacif , Rajesh Kumar , Kazuharu Bamba

Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature-redshift scaling relation. We use the most…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Ivan de Martino

The aim of this paper is to analyze the cosmological evolution of holographic dark energy in $f(\mathcal{G},T)$ gravity ($\mathcal{G}$ and $T$ represent the Gauss-Bonnet invariant and trace of the energy-momentum tensor, respectively). We…

General Relativity and Quantum Cosmology · Physics 2019-04-03 M. Sharif , Ayesha Ikram

The paper deals with a spatially homogeneous and isotropic FRW space-time filled with perfect fluid and dark energy components. The two sources are assumed to interact minimally, and therefore their energy momentum tensors are conserved…

General Relativity and Quantum Cosmology · Physics 2014-08-21 Suresh Kumar

We construct cosmological model in nonmetricity scalar functional gravitational Lagrangian $f(Q)$ which describes the dynamical evolution of the late accelerating universe. Cosmological models are constructed considering different…

General Relativity and Quantum Cosmology · Physics 2025-04-23 Bikash Chandra Roy , Aroonkumar Beesham , Bikash Chandra Paul

In this paper, after reconstructing the redshift evolution of the Hubble function by adopting Gaussian process techniques, we estimate the best-fit parameters for some flat Friedmann cosmological models based on a Modified Chaplygin Gas…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-28 Muhsin Aljaf , Daniele Gregoris , Martiros Khurshudyan

In this paper, we have investigated late time acceleration for a spatially flat dust filled Universe in Brans-Dicke theory in the presence of a positive cosmological constant $\Lambda$ . Expressions for Hubble's constant, luminosity…

General Relativity and Quantum Cosmology · Physics 2017-10-23 G. K. Goswami

In this paper we consider an holographic model of dark energy, where the length scale is the Hubble radius, in a non flat geometry. The model contains the possibility to alleviate the cosmic coincidence problem, and also incorporate a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Victor H. Cardenas , Roberto G. Perez

Keeping in mind the current picture of an accelerating and flat Universe, some specific dynamical models of the cosmological term $\Lambda$ have been selected for investigating the nature of dark energy. Connecting the free parameters of…

Astrophysics · Physics 2008-11-26 Saibal Ray , Utpal Mukhopadhyay , Xin-He Meng

We investigate a late-time cosmological model for a homogeneous and isotropic space-time in the Rastall theory. We explore the observational constraints on the Hubble parameter by using the latest cosmological datasets such as cosmic…

General Relativity and Quantum Cosmology · Physics 2026-01-01 Vinod Kumar Bhardwaj , Saibal Ray , Kazuharu Bamba , Akram Ali

In the present work, we have studied the dynamics of accelerating universe considering a simple parametrization of the equation of state parameter in an interacting scenario. In this toy model, the dark energy component is allowed to…

General Relativity and Quantum Cosmology · Physics 2025-05-23 Sangita Goswami , Sudipta Das

The cosmological constant and many other possible origins for acceleration of the cosmic expansion possess variations in the dark energy properties slow on the Hubble time scale. Given that models with more rapid variation, or even phase…

Astrophysics · Physics 2009-08-21 Eric V. Linder

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 main task of this paper is to realize a cosmic observational compatible universe in the framework of holographic dark energy model when the Hubble horizon $H$ is taken as the role of an IR cut-off. When the model parameter $c$ of a time…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-28 Lixin Xu

In this work, we analyse the late-time evolution of the universe for a particular $f(R)$ gravity model built from an exponential function of the scalar curvature. Following the literature, we write the field equations in terms of a suited…

General Relativity and Quantum Cosmology · Physics 2023-10-18 A. Oliveros , Mario A. Acero

In the paper, we present an accelerating cosmological model in $f(R,\mathcal{L}_{m})$ gravity with the parameter constrained through the cosmological data sets. At the beginning, we have employed a functional form of $f(R,\mathcal{L}_{m})…

General Relativity and Quantum Cosmology · Physics 2025-01-10 Y. Kalpana Devi , S. A. Narawade , B. Mishra

A linear relationship between the Hubble expansion parameter and the time derivative of the scalar field is assumed in order to derive exact analytic cosmological solutions to Einstein's gravity with two fluids: a barotropic perfect fluid…

General Relativity and Quantum Cosmology · Physics 2009-09-29 Olga Arias , Tame Gonzalez , Israel Quiros

In a recent paper \cite{Artymowski:2020zwy} we suggested the possibility that the present acceleration of the Universe is due to thermodynamical behavior of unparticles. The model is free of scalar fields, modified gravity, a Cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Michał Artymowski , Ido Ben-Dayan , Utkarsh Kumar
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