Initial and final de Sitter universes from modified $f(R)$ gravity

Abstract

Viable models of modified gravity which satisfy both local as well as cosmological tests are investigated. It is demonstrated that some versions of such highly non-linear models exhibit multiply de Sitter universe solutions, which often appear in pairs, being one of them stable and the other unstable. It is explicitly shown that, for some values of the parameters, it is possible to find several de Sitter spaces (as a rule, numerically); one of them may serve for the inflationary stage, while the other can be used for the description of the dark energy epoch. The numerical evolution of the effective equation of state parameter is also presented, showing that these models can be considered as natural candidates for the unification of early-time inflation with late-time acceleration through dS critical points. Moreover, based on the de Sitter solutions, multiply SdS universes are constructed which might also appear at the (pre-)inflationary stage. Their thermodynamics are studied and free energies are compared.

25 pages, 8 figures, 2 references added; PRD accepted version

References in corpus (44)

• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Extra force in $f(R)$ modified theories of gravity
• Extended Theories of Gravity and their Cosmological and Astrophysical Applications
• Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion
• Modified f(R) gravity unifying R^m inflation with \LambdaCDM epoch
• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• Constraining f(R) Gravity as a Scalar Tensor Theory
• The Cosmology of f(R) Gravity in the Metric Variational Approach
• Modified gravity with arbitrary coupling between matter and geometry
• Solar system and equivalence principle constraints on f(R) gravity by chameleon approach
• Energy conditions in f(R)-gravity
• Phantom scalar dark energy as modified gravity: understanding the origin of the Big Rip singularity
• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• From inflation to dark energy in the non-minimal modified gravity
• Non-linear evolution of f(R) cosmologies II: power spectrum
• de Sitter space and the equivalence between f(R) and scalar-tensor gravity
• Relativistic stars in f(R) gravity, and absence thereof
• The evolution of density perturbations in f(R) gravity
• Inflationary cosmology and the late-time accelerated expansion of the universe in non-minimal Yang-Mills-$F(R)$ gravity and non-minimal vector-$F(R)$ gravity
• Dark energy from modified F(R)-scalar-Gauss-Bonnet gravity
• Static spherically symmetric perfect fluid solutions in $f(R)$ theories of gravity
• Newton law corrections and instabilities in $f(R)$ gravity with the effective cosmological constant epoch
• Generalized virial theorem in f(R) gravity
• Density perturbations in f(R) gravity theories in metric and Palatini formalisms
• On the non-minimal gravitational coupling to matter
• The phase space view of f(R) gravity
• Can f(R) Modified Gravity Theories Mimic a LCDM Cosmology?
• The viability of theories with matter coupled to the Ricci scalar
• Delicate f(R) gravity models with disappearing cosmological constant and observational constraints on the model parameters
• The Cauchy problem of f(R) gravity
• Generalized second law in modified theory of gravity
• Dynamical systems analysis of anisotropic cosmologies in $R^n$-gravity
• Black hole entropy in modified gravity models
• The effect of modified gravity on weak lensing
• f(R) cosmology with torsion
• Higher-order gravity and the cosmological background of gravitational waves
• Noether Charge and Black Hole Entropy in Modified Theories of Gravity
• Multiple Lambda cosmology: dark fluid with time-dependent equation of state as classical analog of cosmological landscape
• The solution of the cosmological constant problem from the inhomogeneous equation of state - a hint from modified gravity?
• "Detuned" f(R) gravity and dark energy
• Constraining Newtonian stellar configurations in f(R) theories of gravity
• Homogeneous cosmologies in generalized modified gravity
• Higher Powers in Gravitation
• On the stability of spherically symmetric spacetimes in metric f(R) gravity

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• Modified gravity with vacuum polarization