Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion

Abstract

A general approach to viable modified $f(R)$ gravity is developed in both the Jordan and the Einstein frames. A class of exponential, realistic modified gravities is introduced and investigated with care. Special focus is made on step-class models, most promising from the phenomenological viewpoint and which provide a natural way to classify all viable modified gravities. One- and two-steps models are explicitly considered, but the analysis is extensible to $N$-step models. Both inflation in the early universe and the onset of recent accelerated expansion arise in these models in a natural, unified way. Moreover, it is demonstrated that models in this category easily pass all local tests, including stability of spherical body solution, non-violation of Newton's law, and generation of a very heavy positive mass for the additional scalar degree of freedom.

15 pages, 2 figures, version to appear in Physical Review D

References in corpus (28)

• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Extra force in $f(R)$ modified theories of gravity
• Modified f(R) gravity unifying R^m inflation with \LambdaCDM epoch
• Constraining f(R) Gravity as a Scalar Tensor Theory
• The Cosmology of f(R) Gravity in the Metric Variational Approach
• Limit to General Relativity in f(R) theories of gravity
• The Newtonian Limit of F(R) gravity
• Energy conditions in f(R)-gravity
• Phantom scalar dark energy as modified gravity: understanding the origin of the Big Rip singularity
• Stability of Cosmological Solution in f(R) Models of Gravity
• de Sitter space and the equivalence between f(R) and scalar-tensor gravity
• The evolution of density perturbations in 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
• A viability criterion for modified gravity with an extra force
• Newton law corrections and instabilities in $f(R)$ gravity with the effective cosmological constant epoch
• Density perturbations in f(R) gravity theories in metric and Palatini formalisms
• The phase space view of f(R) gravity
• Can f(R) Modified Gravity Theories Mimic a LCDM Cosmology?
• Viable Palatini-f(R) cosmologies with generalized dark matter
• The Cauchy problem of f(R) gravity
• How (Not) to Palatini
• Dynamical systems analysis of anisotropic cosmologies in $R^n$-gravity
• Generalized second law in modified theory of gravity
• 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
• Constraining Newtonian stellar configurations in f(R) theories of gravity
• f(R) Gravities à la Brans-Dicke

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• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• Reconstructing the universe history, from inflation to acceleration, with phantom and canonical scalar fields
• 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
• Weak Lensing Probes of Modified Gravity
• Thin accretion disks in f(R) modified gravity models
• Dark energy, inflation and dark matter from modified F(R) gravity
• F(R) gravity equation of state
• Energy-momentum complexes in f(R) theories of gravity
• Revisiting chameleon gravity - thin-shells and no-shells with appropriate boundary conditions
• Can F(R)-gravity be a viable model: the universal unification scenario for inflation, dark energy and dark matter
• "Detuned" f(R) gravity and dark energy
• Generalized modified gravity models: the stability issue