Scalar–tensor models of normal and phantom dark energy

By R. Gannouji, D. Polarski, André Ranquet, A. Starobinsky. 2006

234 citations recorded by the source corpus.

We consider the viability of dark energy (DE) models in the framework of the scalar–tensor theory of gravity, including the possibility of having a phantom DE at small redshifts z as admitted by supernova luminosity–distance data. For small z, the generic solution for these models is constructed in the form of a power series in z without any approximation. Necessary constraints for DE to be phantom today and to cross the phantom divide line p = −ρ at small z are presented. Considering the solar system constraints, we find for the post-Newtonian parameters that γPN < 1 and γPN,0 ≈ 1 for the model to be viable, and βPN,0 > 1 (but very close to 1) if the model has a significantly phantom DE today. However, prospects for establishing the phantom behaviour of DE are much better with cosmological data than with solar system experiments. Earlier obtained results for a Λ-dominated universe with the vanishing scalar field potential are extended to a more general DE equation of state confirming that the cosmological evolution of these models rules them out. Models of currently phantom DE which are viable for small z can be easily constructed with a constant potential; however, they generically become singular at some higher z. With a growing potential, viable models exist up to an arbitrary high redshift.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/a83e50a44f3ac3bb7703fbdd1a0418ce65f815ba

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Citations in the corpus

Dust of dark energy (2010, background): “Further, abandoning another assumption from [39], that coupling to gravity is minimal, allows one to have a classically stable crossing of the phantom divide in scalar-tensor theories [51–55].”
f(R) Theories (2010, background): “The cosmological dynamics for such nearly flat potentials have been discussed by a number of authors in several classes of scalar-tensor theories [489, 451, 416, 271].”
Curing singularities in cosmological evolution of F(R) gravity (2009, background): “Moreover, as argued in [19], cosmological models with ghosts are unsatisfactory even at the purely classical level.”
Imperfect Dark Energy from Kinetic Gravity Braiding (2010, background): “Thus in this respect, kinetic braiding exhibits similar phenomenology to models with explicit nonminimal coupling to gravity, which also allow one to have a classically stable crossing of the phantom divide in scalar-tensor theories [85, 86, 87, 88].”
Observational constraints on teleparallel dark energy (2011, background): “The first is to modify the content of the universe by introducing the dark energy sector, which can be based on a canonical scalar field (quintessence) [6–22], a phantom field [23–28], or on the combination of both these fields in a unified scenario called quintom [29–35] (see [36] for a review).”