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We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place…

高能物理 - 唯象学 · 物理学 2009-11-10 E. J. Copeland , N. J. Nunes , M. Pospelov

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…

高能物理 - 理论 · 物理学 2010-11-05 Juan M. Romero , J. A. Santiago

In this paper within the scope of FRW cosmology for k = 0, \pm1 we study the dynamics of the universe for a cosmological model with a scalar field nonminimally coupled to matter. By best- fitting the model parameters with the observational…

广义相对论与量子宇宙学 · 物理学 2012-07-09 H. Farajollahi , A. Salehi

A model for a flat isotropic universe with a negative cosmological constant $\Lambda$ and a massless scalar field as sole matter content is studied within the framework of Loop Quantum Cosmology. By application of the methods introduced for…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Eloisa Bentivegna , Tomasz Pawlowski

The purpose of this study is to describe a perfect fluid matter distribution that leads to a constant curvature region, thanks to the effect of a non-minimal coupling. This distribution exhibits a density profile within the range found in…

广义相对论与量子宇宙学 · 物理学 2011-07-04 J. Páramos , O. Bertolami

We numerically construct compact stars in the scalar-tensor theory of gravity with non-minimal derivative coupling of a scalar field to the curvature and nonzero cosmological constant. There are two free parameters in this model of gravity:…

广义相对论与量子宇宙学 · 物理学 2025-04-08 P. E. Kashargin , A. A. Lebedev , S. V. Sushkov

The Hartle-Hawking no-boundary proposal describes the quantum creation of the universe. To have a non-negligible probability to obtain a classical expanding universe, eternal inflation is required, which is severely constrained by Swampland…

广义相对论与量子宇宙学 · 物理学 2020-11-03 Hiroki Matsui , Takahiro Terada

Horndeski models with a de Sitter critical point for any kind of material content may provide a mechanism to alleviate the cosmological constant problem. We study the cosmological evolution of two classes of families - the linear models and…

广义相对论与量子宇宙学 · 物理学 2015-11-03 Nelson J. Nunes , Prado Martin-Moruno , Francisco S. N. Lobo

We consider the dynamics of a scalar field non-minimally coupled to gravity in the context of cosmology. It is demonstrated that there exists a new phase for the scalar field, in addition to the inflationary and dust-like (reheating period)…

宇宙学与河外天体物理 · 物理学 2013-07-30 Amir Ghalee

We observe that the standard homogeneous cosmologies, those of Minkowski, de Sitter, and anti-de Sitter, which form the matrix for the Robertson--Walker scale factor, live naturally as isolated points inside a larger family of conformally…

广义相对论与量子宇宙学 · 物理学 2014-11-19 Jonathan Holland , George Sparling

We use cosmography to present constraints on the kinematics of the Universe without postulating any underlying theoretical model a priori. To this end, we use a Markov Chain Monte Carlo analysis to perform comparisons to the supernova Ia…

宇宙学与河外天体物理 · 物理学 2013-01-18 Alejandro Aviles , Christine Gruber , Orlando Luongo , Hernando Quevedo

We study the phase space analysis of a nonminimally coupled scalar field model with different potentials such as KKLT, Higgs, inverse and inverse square. Our investigation brings new asymptotic regimes, and obtains stable de-Sitter…

广义相对论与量子宇宙学 · 物理学 2021-04-27 M. Shahalam , Shynaray Myrzakul

The presently open problem of the Hubble tension is shown to be removed in the context of a modified theory of gravity with a non-minimal coupling between curvature and matter. By evolving the cosmological parameters that match the cosmic…

广义相对论与量子宇宙学 · 物理学 2024-10-22 Miguel Barroso Varela , Orfeu Bertolami

We consider a nonrelativistic cosmological model introduced in [1] and derived as the nonrelativistic limit (or approximation at sub-Hubble scales) of a general relativistic model in [3, 4]. The latter is defined by an energy-momentum…

综合物理 · 物理学 2017-12-11 Peter C. Stichel

We explore cosmology in the decoupling limit of a non-linear covariant extension of Fierz-Pauli massive gravity obtained recently in arXiv:1007.0443. In this limit the theory is a scalar-tensor model of a unique form defined by symmetries.…

高能物理 - 理论 · 物理学 2011-05-19 Claudia de Rham , Gregory Gabadadze , Lavinia Heisenberg , David Pirtskhalava

We study evolution of cosmological models filled with the scalar field and barotropic matter. We consider the scalar field minimally and non-minimally coupled to gravity. We demonstrated the growth of degree of complexity of evolutional…

宇宙学与河外天体物理 · 物理学 2012-12-20 Orest Hrycyna , Marek Szydlowski

We discuss the Freund-Rubin compactification with cosmological constant and the dilaton field, and examine the stability of the spacetimes at the low energy. The Minkowski or de Sitter spacetime can be obtained if the dilation field is…

高能物理 - 理论 · 物理学 2009-11-07 Takashi Torii , Tetsuya Shiromizu

We consider the relation between exact solutions of cosmological models having minimally and non-minimally coupled scalar fields. This is done for a particular class of solvable models which, in the Einstein frame, have potentials depending…

广义相对论与量子宇宙学 · 物理学 2015-12-15 A. Yu. Kamenshchik , E. O. Pozdeeva , A. Tronconi , G. Venturi , S. Yu. Vernov

Multifield models with a curved field space have already been shown to be able to provide viable quintessence models for steep potentials that satisfy swampland bounds. The simplest dynamical systems of this type are obtained by coupling…

高能物理 - 理论 · 物理学 2020-10-28 Michele Cicoli , Giuseppe Dibitetto , Francisco G. Pedro

Dynamical systems methods are used to study the evolution of the Bianchi I model with a scalar field. We show that inclusion of the non-minimal coupling term between the scalar field and the curvature changes evolution of the model compared…

广义相对论与量子宇宙学 · 物理学 2013-10-09 Orest Hrycyna , Marek Szydlowski