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Several isotropic, homogeneous cosmological models containing a self-interacting minimally coupled scalar field, a perfect fluid source and cosmological constant are solved. New exact, asymptotically stable solutions with an inflationary…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Luis P. Chimento , Alejandro S. Jakubi

We study teleparallel gravitational theories with are invariant under the conformal transformations. Wide family of the gravitational Lagrangians that are invariant under conformal transformations have investigated. Cosmological solutions…

General Relativity and Quantum Cosmology · Physics 2014-06-24 Davood Momeni , Ratbay Myrzakulov

We examine Friedmann-Robertson-Walker models in three spacetime dimensions. The matter content of the models is composed of a perfect fluid, with a $\gamma$-law equation of state, and a homogeneous scalar field minimally coupled to gravity…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Norman Cruz , Cristian Martinez

We study the dynamics of a cosmological model with a perfect fluid and $\mathcal{N}$ fields on a hyperbolic field space interacting via a symmetric potential. We list all late-time solutions, investigate their stability and briefly discuss…

General Relativity and Quantum Cosmology · Physics 2021-06-01 Perseas Christodoulidis , Andronikos Paliathanasis

Using dynamical systems methods, we describe the evolution of a minimally coupled scalar field and a Friedmann-Lemaitre-Robertson-Walker universe in the context of general relativity, which is relevant for inflation and late-time…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Valerio Faraoni , Charles S. Protheroe

In this work, a cosmological model is considered having two scalar fields minimally coupled to gravity with a mixed kinetic term. The model is characterized by the coupling function and the potential function which are assumed to depend on…

General Relativity and Quantum Cosmology · Physics 2023-02-17 Santu Mondal , Roshni Bhaumik , Sourav Dutta , Subenoy Chakraborty

We investigate the existence of Liouville integrable cosmological models in hybrid metric-Palatini theory. Specifically we use the symmetry conditions for the existence of quadratic in the momentum conservation laws for the field equations…

General Relativity and Quantum Cosmology · Physics 2021-06-09 Andronikos Paliathanasis

We apply as selection rule to determine the unknown functions of a cosmological model the existence of Lie point symmetries for the Wheeler-DeWitt equation of quantum gravity. Our cosmological setting consists of a flat…

General Relativity and Quantum Cosmology · Physics 2016-01-01 Andronikos Paliathanasis , Babak Vakili

In a higher-order modified teleparallel theory cosmological we present analytical cosmological solutions. In particular we determine forms of the unknown potential which drives the scalar field such that the field equations form a Liouville…

General Relativity and Quantum Cosmology · Physics 2018-06-11 L. Karpathopoulos , S. Basilakos , G. Leon , A. Paliathanasis , M. Tsamparlis

We consider a cosmological model in a Friedmann--Lema\^{\i}tre--Robertson--Walker background space with an ideal gas defined in Weyl Integrable gravity. In the Einstein-Weyl theory a scalar field is introduced in a geometric way.…

General Relativity and Quantum Cosmology · Physics 2022-08-24 Andronikos Paliathanasis

The Klein-Gordon equations were recently solved in general relativity for the case of a plane-symmetric static massless scalar field with cosmological constant. By analytic continuation, time-dependent solutions can be obtained that…

General Relativity and Quantum Cosmology · Physics 2009-04-22 Chris Vuille , Jocelyn Dunn

We investigate gauge invariant cosmological perturbations in a spatially flat Friedman-Robertson-Walker universe with scalar fields. It is well known that the evolution equation for the gauge invariant quantities has exact solutions in the…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Yasusada Nambu , Atsushi Taruya

We explore the phase-space of a multiscalar-torsion gravitational theory within a cosmological framework characterized by a spatially flat Friedmann-Lema\^{\i}tre-Robertson-Walker model. Our investigation focuses on teleparallelism and…

General Relativity and Quantum Cosmology · Physics 2024-03-07 Genly Leon , Andronikos Paliathanasis , Alfredo D. Millano

We investigate the cosmological dynamics in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker geometry in scalar-tensor and scalar-torsion theories where the nonminimally coupled scalar field is a complex field. We derive the…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Andronikos Paliathanasis

We consider a Lorentz violating scalar field cosmological model given by the modified Einstein-aether theory defined in Weyl integrable geometry. The existence of exact and analytic solutions is investigated for the case of a spatially flat…

General Relativity and Quantum Cosmology · Physics 2021-04-07 Andronikos Paliathanasis , Genly Leon

We review a system of autonomous differential equations developed in our previous work [1] describing a flat cosmology filled with a barotropic fluid and a scalar field with a modified kinetic term of the form L=F(X)-V(phi). We analyze the…

General Relativity and Quantum Cosmology · Physics 2014-04-04 Josue De-Santiago , Jorge L. Cervantes-Cota

We derive a set of equations monitoring the evolution of covariant and gauge-invariant linear scalar perturbations of Friedman-Lema\^itre-Robertson-Walker models with multiple interacting non-linear scalar fields. We use a dynamical…

General Relativity and Quantum Cosmology · Physics 2014-08-06 Artur Alho , Filipe C. Mena

We study the cosmological evolution of the field equations in the context of Einstein-Aether cosmology by including a scalar field in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker spacetime. Our analysis is separated into two…

General Relativity and Quantum Cosmology · Physics 2020-01-17 Andronikos Paliathanasis , G. Papagiannopoulos , Spyros Basilakos , John D. Barrow

We approach the cosmological inflation thought symmetries of differential equations. We consider the general inflaton field in a homogeneous Friedmann--Lema\^{\i}tre--Robertson--Walker spacetime and with the use of conformal transformations…

General Relativity and Quantum Cosmology · Physics 2019-10-02 Andronikos Paliathanasis

A scale invariant, Weyl geometric, Lagrangian approach to cosmology is explored, with a a scalar field phi of (scale) weight -1 as a crucial ingredient besides classical matter \cite{Tann:Diss,Drechsler:Higgs}. For a particularly simple…

Astrophysics · Physics 2009-11-18 Erhard Scholz
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