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We study general properties of attractors for tachyonic potential chameleon scalar-field model which possess cosmological scaling solutions. An analytic formulation is given to obtain fixed points with a discussion on their stability. The…

General Relativity and Quantum Cosmology · Physics 2015-05-28 H. Farajollahi , A. Salehi , F. Tayebi , A. Ravanpak

We study inflation, perturbations, non-gaussinity and late-time cosmological dynamics of a tachyon field both minimally and non-minimally coupled to gravity. By analyzing the parameters space of the model, the viability of the model in…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Kourosh Nozari , Narges Rshidi

We study the role that tachyon fields may play in cosmology as compared to the well-established use of minimally coupled scalar fields. We first elaborate on a kind of correspondence existing between tachyons and minimally coupled scalar…

High Energy Physics - Theory · Physics 2009-11-10 V. Gorini , A. Yu. Kamenshchik , U. Moschella , V. Pasquier

It has been recently shown that tachyonic chameleon model of dark energy in which tachyon scalar field non-minimally coupled to the matter admits stable scaling attractor solution that could give rise to the late-time accelerated expansion…

General Relativity and Quantum Cosmology · Physics 2018-03-21 A. Banijamali , S. Bellucci , B. Fazlpour , M. Solbi

In this paper, we study the phase space analysis of locally rotationally symmetric Bianchi type I universe model by taking interactions between dark matter and scalar field models. We define normalized dimensionless variables to develop an…

General Relativity and Quantum Cosmology · Physics 2019-08-07 M. Sharif , Saadia Mumtaz

We present a detailed study of cosmological effects of homogeneous tachyon matter coexisting with non-relativistic matter and radiation, concentrating on the inverse square potential and the exponential potential for the tachyonic scalar…

Astrophysics · Physics 2011-05-05 J. S. Bagla , H. K. Jassal , T. Padmanabhan

We study the dynamics of the scalar tensor cosmological model in the presence of tachyon field. In an alternative approach, in two exponential and power law form of the scalar field functions in the model, field equations are solved by…

General Relativity and Quantum Cosmology · Physics 2011-11-22 H. Farajollahi , A. Salehi , A. Shahabi

We investigate in detail the asymptotic properties of tachyon cosmology for a broad class of self-interaction potentials. The present approach relies in an appropriate re-definition of the tachyon field, which, in conjunction with a method…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Israel Quiros , Tame Gonzalez , Dania Gonzalez , Yunelsy Napoles , Ricardo Garcia-Salcedo , Claudia Moreno

We present and examine a kinetically coupled tachyon dark energy model, where a tachyon scalar field interacts with the matter sector. More specifically, we deduce this cosmological setting from a generalised interacting dark energy model…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Francesco Pace , Alberto Rozas-Fernández , Özgen Tunç Türker

The stability criteria for spatially flat homogeneous and isotropic cosmological dynamical system is investigated with the interaction of a scalar field endowed with a perfect fluid.In this paper, we depict the dynamical system perspective…

General Relativity and Quantum Cosmology · Physics 2021-01-25 S. Surendra Singh , Chingtham Sonia

We generalize the scalar tensor bigravity models to the non-minimal kinetic coupling scalar tensor bigravity models with two scalar fields whose kinetic terms are non-minimally coupled to two Einstein tensors constructed by two metrics. We…

General Relativity and Quantum Cosmology · Physics 2015-08-06 F. Darabi , M. Mousavi

We study a tachyon model with non-minimal derivative coupling to gravity in the Friedmann-Robertson-Walker flat cosmology. We propose the special re-definition of the tachyon field which allows us to represent tachyon field equation…

General Relativity and Quantum Cosmology · Physics 2012-09-13 V. K. Shchigolev , M. P. Rotova

We consider the perturbative stability of non-supersymmetric configurations in N=1 supergravity models with a spectator sector not involved in supersymmetry breaking. Motivated by the supergravity description of complex structure moduli in…

High Energy Physics - Theory · Physics 2015-02-23 Kepa Sousa , Pablo Ortiz

We study dynamics of generalized tachyon scalar field in the framework of teleparallel gravity. This model is an extension of tachyonic teleparallel dark energy model which has been proposed in [26]. In contrast with tachyonic teleparallel…

General Relativity and Quantum Cosmology · Physics 2014-08-04 Behnaz Fazlpour , Ali Banijamali

In this work we investigate a cosmological model with the tachyon and fermion fields with barotropic equation of state, where pressure $p$, energy density $\rho$ and barotropic index $\gamma$ are related by the relation $p=(\gamma-1)\rho$.…

General Relativity and Quantum Cosmology · Physics 2021-11-10 P. Tsyba , O. Razina , N. Suikimbayeva

We show how the scalar field, a candidate of quintessence, in a proposed model of the scalar-tensor theories of gravity provides a way to understand a small but nonzero cosmological constant as indicated by recent observations. A particular…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Yasunori Fujii

We study FRW cosmology for scalar tensor theory where two scalar functions nonminimally coupled to the geometry and matter Lagrangian. In a framework to study stability and attractor solutions of the model in the phase space, we…

General Relativity and Quantum Cosmology · Physics 2011-11-22 Hossein Farajollahi , Amin Salehi , Mohammad Nasiri

A qualitative analysis of a scalar-tensor cosmological model, with an exponential potential for the scalar field, is performed. The phase diagram for the flat case is constructed. It is shown that solutions with an initial and final…

General Relativity and Quantum Cosmology · Physics 2016-08-31 A. B. Batista , J. C. Fabris , S. V. B. Goncalves , J. Tossa

We consider here the dynamics of some homogeneous and isotropic cosmological models with $N$ interacting classical scalar fields non-minimally coupled to the spacetime curvature, as an attempt to generalize some recent results obtained for…

General Relativity and Quantum Cosmology · Physics 2007-05-23 L. Brenig , A. Figueiredo , E. Gunzig , T. M. Rocha Filho , Alberto Saa

We study general properties of attractors for scalar-field dark energy scenarios which possess cosmological scaling solutions. In all such models there exists a scalar-field dominant solution with an energy fraction \Omega_{\phi}=1 together…

High Energy Physics - Theory · Physics 2008-11-26 Shinji Tsujikawa
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