Cosmological models with dynamical lambda in scalar-tensor theories

Abstract

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 is used for the matter content of the Universe. Some Friedmann- Robertson-Walker exact solutions are found, they have scale factor wich shows exponential or power law dependence on time. For some models the singularity can be avoided. Cosmological parameters as ${\Omega }_m$, ${\Omega }_{\Lambda }$, $q_0$ and $t_0$ are obtained and compared with observational data.

20 pages, Latex file, a sign in Eq. (2.17) was corrected, reference [37] was corrected

References in corpus (11)

• Evolution of the Scale Factor with a Variable Cosmological Term
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• Scale invariance, new inflation and decaying Lambda terms
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• Stochastic Gravity
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• Spontaneous Decay of the Effective Cosmological Constant

Cited by in corpus (12)

• Late time acceleration in Brans Dicke Cosmology
• Self interacting Brans Dicke cosmology and Quintessence
• Nonsingular vacuum cosmologies with a variable cosmological term
• Modified Brans-Dicke Theory in Arbitrary Dimensions
• Supergravity in Two Spacetime Dimensions
• Required Conditions for Late Time Acceleration and Early Time Deceleration in Generalized Scalar-Tensor Theories
• A model for time-dependent cosmological constant
• Scalar fields in the nonsymmetric Kaluza-Klein (Jordan-Thiry) theory
• Bianchi {VI}${}_0$ in Scalar and Scalar-Tensor Cosmologies
• Cosmological models in the nonsymmetric Kaluza-Klein Theory
• Time-dependent cosmological constant in the Jackiw-Teitelboim cosmology
• Dynamics of Higgs" Fields and a Quintessence in the Nonsymmetric Kaluza-Klein (Jordan-Thiry) Theory