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The recent transition from decelerated to accelerated expansion can be seen as a reflection (or "bounce") in the connection variable, defined by the inverse comoving Hubble length ($b=\dot a$, on-shell). We study the quantum cosmology of…

General Relativity and Quantum Cosmology · Physics 2022-10-06 Bruno Alexandre , Joao Magueijo

We consider a dynamic scenario for characterizing the late Universe evolution, aiming to mitigate the Hubble tension. Specifically, we consider a metric $f(R)$ gravity in the Jordan frame which is implemented to the dynamics of a flat…

General Relativity and Quantum Cosmology · Physics 2024-08-06 Giovanni Montani , Nakia Carlevaro , Mariaveronica De Angelis

In this paper, the dynamical behavior of the accelerated expansion of the universe is studied within the framework of $f(T)$ gravity by considering a well-motivated functional form of $f(T)$. A specific form of the Hubble parameter is…

General Relativity and Quantum Cosmology · Physics 2026-03-20 Khomesh R. Patle , G. P. Singh

Some properties of cosmological models with a time variable bulk viscous coefficient in presence of adiabatic mater creation and G, c, Lambda variables are investigated in the framework of flat FRW line element. We trivially find a set of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 J. A. Belinchon

We investigate late-time cosmology in the context of modified $f(Q,L_m)$ gravity, considering a non-linear model$ f(Q,L_m) = \alpha Q + \beta L_m^n + \lambda$ where, $\alpha$, $\beta$, $\lambda$, and $n$ are some free parameters. The…

General Relativity and Quantum Cosmology · Physics 2026-01-16 Rajdeep Mazumdar , Kalyan Malakar , Kalyan Bhuyan

We investigate in detail the possibility that a single imperfect fluid with bulk viscosity can replace the need for separate dark matter and dark energy in cosmological models. With suitable choices of model parameters, we show that the…

General Relativity and Quantum Cosmology · Physics 2009-07-30 Baojiu Li , John D. Barrow

The cosmological dynamics in the early universe are investigated to explore the possibility of the sign reversal of the Hubble parameter as a key feature of non-singular bouncing cosmological solutions in higher-order torsion gravity. The…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Adnan Malik , Aimen Rauf , Kazuharu Bamba , Wenbin Lin , Fatemah Mofarreh

We investigate the matter density perturbation $\delta_m$ and power spectrum $P(k)$ in the running vacuum model (RVM) with the cosmological constant being a function of the Hubble parameter, given by $\Lambda = \Lambda_0 + 6 \sigma H H_0+…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-09 Chao-Qiang Geng , Chung-Chi Lee

In this paper, we have presented the cosmological model of the Universe that represents late time cosmic acceleration in torsion based gravitational theory, the $f(T)$ gravity. A well motivated parametrization for the Hubble parameter has…

General Relativity and Quantum Cosmology · Physics 2025-11-04 Suraj Kumar Behera , Pratik P. Ray , B. Mishra

Recent cosmic microwave background (CMB) measurements over a large range of angular scales have become sensitive enough to provide interesting constraints on cosmological parameters within a restricted class of models. We use the CMB…

Astrophysics · Physics 2008-02-03 Charles H. Lineweaver , Domingos Barbosa

Bianchi type V viscous fluid cosmological model for barotropic fluid distribution with varying cosmological term $\Lambda$ is investigated. We have examined a cosmological scenario proposing a variation law for Hubble parameter $H$ in the…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Raj Bali , Pratibha Singh , J. P. Singh

We compile an updated list of 38 measurements of the Hubble parameter $H(z)$ between redshifts $0.07 \leq z \leq 2.36$ and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 Omer Farooq , Foram Madiyar , Sara Crandall , Bharat Ratra

We derive an observational constraint on a spherical inhomogeneity of the void centered at our position from the angular power spectrum of the cosmic microwave background(CMB) and local measurements of the Hubble parameter. The late time…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Masato Tokutake , Kiyotomo Ichiki , Chul-Moon Yoo

We prove here that Newtons universal gravitation and momentum conservation laws together reproduce Weinbergs relation. It is shown that the Hubble parameter H must be built in this relation, or equivalently the age of the Universe t. Using…

General Physics · Physics 2011-04-11 Antonio Alfonso-Faus

We study cosmological perturbations in the context of an interacting dark energy model, in which the cosmological term decays linearly with the Hubble parameter, with concomitant matter production. A previous joint analysis of the…

Astrophysics · Physics 2008-11-26 H. A. Borges , S. Carneiro , J. C. Fabris , C. Pigozzo

This lecture provides us with Newtonian approaches for the interpretation of two puzzling cosmological observations that are still discussed subject : a bulk flow and a foam like structure in the distribution of galaxies. For the first one,…

General Relativity and Quantum Cosmology · Physics 2009-11-13 Roland Triay , Henri-Hugues Fliche

The last phase transition predicted by the standard model of particle physics took place at the QCD scale $T\sim200$ MeV when the universe was about $t\sim10^{-5}$ seconds old and the Hubble radius was around 10 Km. In this paper, we…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Malihe Heydari-Fard , Hamid Reza Sepangi

We investigate the effects of viscosity terms depending on the Hubble parameter and its derivatives in the dark energy equation of state. Such terms are possible if dark energy is a fictitious fluid originating from corrections to the…

Astrophysics · Physics 2010-04-06 S. Capozziello , V. F. Cardone , E. Elizalde , S. Nojiri , S. D. Odintsov

In this paper, we investigate the evolution of cosmological perturbations within the context of Bianchi Type$-I$ spacetimes. We consider models containing viscous fluids with evolving cosmological (\LL) and Newtonian gravitational (G)…

General Relativity and Quantum Cosmology · Physics 2023-11-08 Alnadhief H. A. Alfedeel , Maye Elmardi , Amare abebe

We discuss cosmology based on a Cuscuta-Galileon gravity theory, which preserves just two degrees of freedom. Although there exists no additional degrees of freedom, introduction of a potential of a scalar field changes the dynamics. The…

General Relativity and Quantum Cosmology · Physics 2022-05-17 Kei-ichi Maeda , Sirachak Panpanich
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