Cosmic Acceleration and Modified Gravitational Models

Abstract

There is now overwhelming observational evidence that our Universe is accelerating in its expansion. I discuss how modified gravitational models can provide an explanation for this observed late-time cosmic acceleration. We consider specific low-curvature corrections to the Einstein-Hilbert action. Many of these models generically contain unstable de Sitter solutions and, depending on the parameters of the theory, late-time accelerating attractor solutions.

11 pages, 3 figures, references added; Based on talks given at MRST-04, PASCOS-04 and COSMO-04

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• Observational signatures of f(R) dark energy models that satisfy cosmological and local gravity constraints
• Modified gravity and its reconstruction from the universe expansion history
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• The (pseudo)issue of the conformal frame revisited
• Solar System experiments do not yet veto modified gravity models
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• f(R) gravity theories in Palatini formalism: cosmological dynamics and observational constraints
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• Probing a nonlinear electrodynamics black hole with thin accretion disk, shadow and deflection angle with M87* and Sgr A* from EHT
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• Density perturbations in f(R) gravity theories in metric and Palatini formalisms
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• The phase space view of f(R) gravity
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• The Cosmology of Ricci-Tensor-Squared Gravity in the Palatini Variational Approach
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• CMB and Matter Power Spectra of Early f(R) Cosmology in Palatini Formalism
• The Cauchy problem of f(R) gravity
• The relation between F(R) gravity and Einstein-conformally invariant Maxwell source
• Generalized second law in modified theory of gravity
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• Consistency of $f(R)=\sqrt{R^2-R_0^2}$ Gravity with the Cosmological Observations in Palatini Formalism
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• Standard Cosmological Evolution in a Wide Range of f(R) Models
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• Dynamics of a parametrized dark energy model in $f(R,T)$ gravity
• Duality extended Chaplygin cosmologies with a big rip
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• An analytic model for the transition from decelerated to accelerated cosmic expansion
• Testing Alternative Theories of Dark Matter with the CMB
• Holographic Dark Energy Like in $f(R)$ Gravity
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• Correspondence between modified gravity and 5D Ricci-flat cosmologies
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