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We consider a chiral cosmological model in the framework of Einstein-Gauss-Bonnet cosmology. Using a decomposition of the latter equations in such a way that the first chiral field is responsible for the Einstein part of the model, while…

General Relativity and Quantum Cosmology · Physics 2017-12-06 Sunil D. Maharaj , Aroonkumar Beesham , Sergey V. Chervon , Aleksandr S. Kubasov

We obtain cosmological solutions which admit emergent universe (EU) scenario in the framework of Einstein Gauss-Bonnet gravity coupled with a dilaton field in four dimensions. The coupling parameter of the Gauss-Bonnet terms and the dilaton…

High Energy Physics - Theory · Physics 2015-05-13 B C Paul , S Ghose

In this work, we analyze the Einstein-scalar-Gauss-Bonnet (EsGB) theory of gravity in a cosmological context using the formalism of dynamical systems. We obtain the equations of motion of the theory and introduce an appropriate set of…

General Relativity and Quantum Cosmology · Physics 2025-09-23 Miguel A. S. Pinto , João Luís Rosa

We explore the possibility of emergent cosmology using the effective potential formalism. We discover new models of emergent cosmology which satisfy the constraints posed by the cosmic microwave background (CMB). We demonstrate that, within…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Satadru Bag , Varun Sahni , Yuri Shtanov , Sanil Unnikrishnan

Theoretical arguments and cosmological observations suggest that Einstein's theory of general relativity needs to be modified at high energies. One of the best motivated higher-curvature extensions of general relativity is…

General Relativity and Quantum Cosmology · Physics 2017-08-04 Laura Sberna

We consider the emergent universe scenario supported by a chiral cosmological model with two interacting dark sector fields: phantom and canonical. We investigate the general properties of the evolution of the kinetic and potential energies…

General Relativity and Quantum Cosmology · Physics 2013-12-09 A. Beesham , S. V. Chervon , S. D. Maharaj , A. S. Kubasov

We present modified Gauss-Bonnet gravity without matter in four dimensions which accommodates flat emergent universe (EU) obtained in Einstein's general theory of gravity with a non-linear equation of state. The EU model is interesting…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 B. C. Paul , S. D. Maharaj , A. Beesham

In this paper, in an FLRW background and a perfect fluid equation of state, we explore the possibility of the realization of an emergent scenario in a 4D regularized extension of Einstein-Gauss-Bonnet gravity, with the field equations…

General Relativity and Quantum Cosmology · Physics 2024-06-12 Mrinnoy M. Gohain , Kalyan Bhuyan

We present new classes of exact solutions for an Emergent Universe supported by phantom and canonical scalar fields in the framework of a two-component chiral cosmological model. We outline in detail the method of deriving exact solutions,…

General Relativity and Quantum Cosmology · Physics 2013-12-06 A. Beesham , S. V. Chervon , S. D. Maharaj , A. S. Kubasov

Einstein-Gauss-Bonnet (EGB) model is recently restudied in order to analyze new consequences in gravitation, modifying appropriately the Einstein-Hilbert action. The consequences in EGB cosmology are mainly geometric, with higher order…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-02 Miguel A. García-Aspeitia , A. Hernández-Almada

Some models within the framework of Gauss-Bonnet gravities are considered in the presence of a non-minimally coupled scalar field. By imposing a particular constraint on the scalar field coupling, an extension of the called…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Sergei D. Odintsov , Diego Saez-Chillon Gomez , German S. Sharov

This paper analyzes the possibility of bouncing and non-bouncing universes in the framework of four-dimensional Einstein-Gauss-Bonnet (4D-EGB) gravity, corresponding respectively to negative and positive coupling constants $\lambda$ of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 H. Khodabakhshi , M. Farhang , H. Lü

Einstenian cubic gravity (ECG) is a modified theory of gravity constructed with cubic contractions of the curvature tensor. This theory has the remarkable feature of having the same two propagating degrees of freedom of Einstein gravity…

General Relativity and Quantum Cosmology · Physics 2024-06-04 L. A. Lessa , R. V. Maluf , J. E. G. Silva , C. A. S. Almeida

We study the cosmological model based on Einstein-Gauss-Bonnet gravity with non-minimal coupling of a scalar field to a Gauss-Bonnet term in 4D Friedmann universe. We show how constructing the exact solutions by the method based on a…

General Relativity and Quantum Cosmology · Physics 2017-07-26 Igor V. Fomin , Sergey V. Chervon

We consider alternative inflationary cosmologies in massive gravity with degenerate reference metrics and study the feasibilities of the emergent universe scenario, bouncing and cyclic universes. We focus on the construction of the Einstein…

General Relativity and Quantum Cosmology · Physics 2019-05-28 Shou-Long Li , H. Lü , Hao Wei , Puxun Wu , Hongwei Yu

A modified Einstein-Gauss-Bonnet gravity in four dimensions where the quadratic Gauss-Bonnet term is coupled to a scalar field is considered. The field equations of the model are obtained by variational methods by making use of the…

General Relativity and Quantum Cosmology · Physics 2016-08-30 Hatice Özer , Ahmet Baykal , Özgür Delice

To seek for a singularity free model universe from a perfect fluid scalar-metric cosmology, we work in the "\emph{Emergent Cosmology}" (EC) paradigm which is a non-singular alternative for cosmological inflation. By using two methods…

General Relativity and Quantum Cosmology · Physics 2018-06-26 Mohsen Khodadi , Kourosh Nozari

Our paper introduces a new theoretical framework called the Fractional Einstein--Gauss--Bonnet scalar field cosmology, which has important physical implications. Using fractional calculus to modify the gravitational action integral, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-12 Bayron Micolta-Riascos , Alfredo D. Millano , Genly Leon , Byron Droguett , Esteban González , Juan Magaña

We study modified $f(R,(\nabla R)^2,\square R)$ gravity and show in detail how it can be reduced to Einstein gravity with a few scalar fields and then represented in the form of chiral self-gravitating model of the special type. In further…

General Relativity and Quantum Cosmology · Physics 2024-10-10 Tatyana Chaadaeva , Sergey Chervon

In order to bypass the big bang singularity, we develop an emergent universe scenario within a covariant extension of General Relativity known as \emph{"Energy-Momentum Squared Gravity"}. The extra terms of the model emerge in the high…

General Relativity and Quantum Cosmology · Physics 2022-04-05 Mohsen Khodadi , Alireza Allahyari , Salvatore Capozziello
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