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We consider an anisotropic cosmological model based on the locally rotational Bianchi I spacetime, incorporating a scalar field and a non-zero cosmological interaction term. The framework of averaging theory is employed to study the…

General Relativity and Quantum Cosmology · Physics 2025-08-06 Alfredo D. Millano , Genly Leon , Andronikos Paliathanasis

In this paper, we investigate inhomogeneous viscous fluid cosmology for inflation. Several toy models are presented in the attempt to analyze how inflation can be realized according with cosmological data by making use of an inhomogeneous…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Ratbay Myrzakulov , Lorenzo Sebastiani

We consider the cosmological evolution of a flat anisotropic Universe in $f(T)$ gravity in the presence of a perfect fluid. It is shown that the matter content of the Universe has a significant impact of the nature of a cosmological…

General Relativity and Quantum Cosmology · Physics 2021-06-10 Maria A. Skugoreva , Alexey V. Toporensky

We present an interacting model with a phenomenological interaction, $\bar{Q}$, between a cold dark matter (DM) fluid and a dark energy (DE) fluid, which takes a time-varying equation of state (EoS) parameter, $\mathrm{\omega_{DE}}$. Here,…

General Relativity and Quantum Cosmology · Physics 2018-06-04 Freddy Cueva Solano

We investigate interacting ghost dark energy models in higher dimensional cosmology. We attempt to model dark matter within a barotropic fluid with $P_{b}=\omega(t)_{b}\rho$. In this work we consider four different models based on choosing…

General Relativity and Quantum Cosmology · Physics 2016-05-25 J. Sadeghi , M. Khurshudyan , H. Farahani

In this paper, the cosmological "constant" and the Hubble parameter are considered in the Weyl theory of gravity, by taking them as functions of $r$ and $t$, respectively. Based on this theory and in the linear approximation, we obtain the…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Mohammad Reza Tanhayi , Mohsen Fathi , Mohammad Vahid Takook

We study a Newtonian cosmological model in the context of a noncommutative space. It is shown that the trajectories of a test particle undergo modifications such that it no longer satisfies the cosmological principle. For the case of a…

High Energy Physics - Theory · Physics 2010-11-05 Juan M. Romero , J. A. Santiago

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

The tensions between the values of Hubble constant obtained from the early and the late Universe data pose a significant challenge to modern cosmology. Possible modifications of the flat homogeneous isotropic cosmological {\Lambda}CDM model…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-14 S. L. Parnovsky

To find more deliberate f(R,T) cosmological solutions, we proceed our previous paper further by studying some new aspects of the considered models via investigation of some new cosmological parameters/quantities to attain the most…

General Relativity and Quantum Cosmology · Physics 2017-05-23 Hamid Shabani , Mehrdad Farhoudi

We propose a new type of cosmological model derived from the fractional variational principle when it is applied to the gravitational sector of action functional. In contrast to the fractional cosmological model developed earlier by the…

General Relativity and Quantum Cosmology · Physics 2013-04-30 V. K. Shchigolev

In the action formalism variations of metric tensors usually are limited by the Hubble horizon. Contrary, variations of quantum fields should be extended up to the event horizon, which is the real boundary of the spacetime. As the result…

General Physics · Physics 2018-11-29 Merab Gogberashvili

We investigate the tachyonic cosmological potential $V(\phi)$ in two different cases of the quasi-exponential expansion of universe and discuss various forms of interaction between the two components---matter and the cosmological…

General Physics · Physics 2012-07-12 Murli Manohar Verma , Shankar Dayal Pathak

The standard model of cosmology is investigated using time dependent cosmological constant $\Lambda$ and Newton's gravitational constant $G$. The total energy content is described by the modified Chaplygin gas equation of state. It is found…

General Relativity and Quantum Cosmology · Physics 2009-03-12 Mubasher Jamil , Farook Rahaman , Mehedi Kalam

Non-gravitational interaction between two barotropic dark fluids, namely the pressureless dust and the dark energy in a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker model has been discussed. It is shown that for the interactions…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-30 Supriya Pan , Ankan Mukherjee , Narayan Banerjee

In this paper, two inhomogeneous single fluid models for the Universe, which are able to naturally solve the $H_{0}$ tension problem, are discussed. The analysis is based on a Bayesian Machine Learning approach that uses a generative…

General Relativity and Quantum Cosmology · Physics 2020-12-09 Emilio Elizalde , Martiros Khurshudyan , Sergei D. Odintsov , Ratbay Myrzakulov

In general relativity, for fluids with a linear equation of state (EoS) or scalar fields, the high isotropy of the universe requires special initial conditions, and singularities are anisotropic in general. In the brane world scenario…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Kishore N. Ananda , Marco Bruni

The disagreement between low- and high-redshift measurements of the Hubble parameter is emerging as a serious challenge to the standard model of cosmology. We develop a covariant cosmographic analysis of the Hubble parameter in a general…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-13 Roy Maartens , Jessica Santiago , Chris Clarkson , Basheer Kalbouneh , Christian Marinoni

In the context of a family os scalar-tensor theories with a dynamical $\Lambda$, that is a binomial on the scalar field, the cosmological equations are considered. A general barotropic state equation $p=(\gamma-1)\rho$, for a perfect fluid…

General Relativity and Quantum Cosmology · Physics 2009-10-31 L. M. Diaz-Rivera , L. O. Pimentel

In the realm of the Bekenstein-Hawking entropy, the thermodynamics of apparent horizon bridges with the usual FLRW (Friedmann-Lema\^{i}tre-Robertson-Walker) equation only for a special case where the matter field is given by a perfect fluid…

General Relativity and Quantum Cosmology · Physics 2022-12-14 Shin'ichi Nojiri , Sergei D. Odintsov , Tanmoy Paul
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