Inflationary Cosmology in Modified Gravity Theories

Inflationary Cosmology in Modified Gravity Theories

We review inflationary cosmology in modified gravity such as R gravity with its extensions in order to generalize the Starobinsky inflation model. In particular, we explore inflation realized by three kinds of effects: modification of gravity, the quantum anomaly, and the R term in loop quantum cosmology. It is explicitly demonstrated that in these inflationary models, the spectral index of sca...

Comments on ’ Regular inflationary cosmology and gauge theories of gravity ’

In this note we comment recent paper by A.V. Minkevich 'Regular inflationary cosmology and gauge theories of gravity' on the 'bouncing' character of flat-type inflationary cosmolog-ical models within gauge theories of gravity. Recently [1] it was argued that inflationary cosmological solutions in the case of flat models within the framework of gauge theories of gravity have 'bouncing' character...

Inflationary cosmology from STM theory of gravity

I study the power-law and de Sitter expansions for the universe during inflation from the STM theory of gravity. In a de Sitter expansion the additional dimension is related to the cosmological constant Λ = 3/ψ2. I find from experimental data that the mass of the inflaton field is m2 = 2/(3ψ2). In power-law expansion, the fifth coordinate (ψ) appears to be a dimensionless constant. The interest...

Modified gravity and cosmology

Constraints on Scalar-Tensor Theories of Gravity from Density Perturbations in Inflationary Cosmology

Spectra of density perturbations produced during chaotic inflation in scalartensor theories of gravity are calculated, taking both adiabatic and isocurvature modes into account. Comparing the predicted spectrum of the cosmic microwave background radiation anisotropies with the one observed by the COBE-DMR we calculate constraints on the parameters of these theories, which turn out to be stronge...