Remarks on generalized scalar-tensor models of dark energy

Abstract

The generalized scalar-tensor models with Lagrangian $F(\varphi ,R)-U(\varphi )(\nabla \varphi {)}^2$ are considered. It is shown that the phantom-divide-line crossing and the deceleration to acceleration transition generally occurr in these models. Two specific examples, the coupled quintessence model and the Brans-Dicke model are considered. For the first example, it is shown that for the models with $\xi >3/16$, the $\omega =-1$ transition exists. This is verified numerically for some special cases. For the Brans-Dicke model, it is shown that the transition does not occur, a result which can be verified by using the exact solution of this model. Finally the contribution of quantum effects on these phenomena is investigated. It is shown that for some special cases where the $\omega =-1$ transition is classically forbidden, the quantum effects can induce transition. The $\xi =1/6$ of coupled quintessence model is an example of this. The quantum effects are described via the account of conformal anomaly.

20 pages, 5 figures, typos corrected, reference added

References in corpus (20)

• Dark energy in modified Gauss-Bonnet gravity: late-time acceleration and the hierarchy problem
• Cosmological parameters from combining the Lyman-alpha forest with CMB, galaxy clustering and SN constraints
• The Dynamics of Quintessence, The Quintessence of Dynamics
• Reconstructing holographic quintessence
• Constraints on scalar-tensor models of dark energy from observational and local gravity tests
• Cosmological coincidence problem in interacting dark energy models
• A viability criterion for modified gravity with an extra force
• Quintom cosmologies with arbitrary potentials
• Transition from quintessence to phantom phase in quintom model
• Phantom field dynamics in loop quantum cosmology
• Remarks on generalized Gauss-Bonnet dark energy
• A New Approach to Quintessence and a Solution of Multiple Attractors
• Extended Quintessence with non-minimally coupled phantom scalar field
• Standard Cosmological Evolution in a Wide Range of f(R) Models
• The w = -1 crossing of the quintom model with slowly-varying potentials
• Quantum Corrections in Quintessence Models
• Route to Lambda in conformally coupled phantom cosmology
• Asymptotic behavior of w in general quintom model
• The dynamics of scalar-tensor cosmology from RS two-brane model
• Quantum induced w = -1 crossing of the quintessence and phantom models

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• Reconstructing inflation in scalar-torsion $f(T,\varphi )$ gravity
• Cosmic Dynamics in $F(R,\varphi )$ Gravity
• Cosmological aspects of $f(R,T)$ gravity in a simple model with a parametrization of $q$
• On Dark Energy and Accelerated Reference Frames