Cosmic acceleration and geodesic deviation in chameleon scalar field model

An interacting scalar field and the recent cosmic acceleration

In this paper it is shown that the Brans Dicke scalar field itself can serve the purpose of providing an early deceleration and a late time acceleration of the universe without any need of quintessence field if one considers an interaction, i.e, transfer of energy between the dark matter and the Brans Dicke scalar field.

Geodesic Deviation and Weak-Field Solutions

Cosmic Acceleration, Scalar Fields and Observations

Conditions for accelerated expansion of Friedmann–Robertson–Walker space–time are analyzed. Connection of this scenario with present–day observations are reviewed. It is explained how a scalar field could be responsible for cosmic acceleration observed in present times and predicted for the very early Universe. Ideas aimed at answering whether is that the actual case for our Universe are descri...

Brans-Dicke Scalar Field as a Chameleon

In this paper it is shown that in Brans Dicke theory, if one considers a non-minimal coupling between the matter and the scalar field, it can give rise to a late time accelerated expansion for the universe preceded by a decelerated expansion for very high values of the Brans Dicke parameter ω.

New Type Scalar Fields for Cosmic Acceleration

We present a model where a non-conventional scalar field may act like dark energy leading to cosmic acceleration. The latter is driven by an appropriate field configuration, which result in an effective cosmological constant. The potential role of such a scalar in the cosmological constant problem is also discussed. ∗e-mail: [email protected] June 2006 During the last years, evidence of an accel...