Cosmology of f(R,❑R) gravity

Modified gravity and cosmology

Lorentzian Gravity and Cosmology

If a material vacuum exists, with the properties of a superfluid through which already recognized material moves, then it is capable of acting as a universal reference frame and as an intermediary for the production of particle pairs throughout the universe, which as they cool and recombine, become the source of both high-and low-temperature cosmic background radiation, as observed. Moreover, i...

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...

Quantum Cosmology of Classically Constrained Gravity

In hep-th/0506040 we discussed a classically constrained model of gravity. This theory contains known solutions of General Relativity (GR), and admits solutions that are absent in GR. Here we study cosmological implications of some of these new solutions. We show that a spatially-flat de Sitter universe can be created from “nothing”. This universe has boundaries, and its total energy equals to ...

Non-singular Cosmology in Modified Gravity

A non-singular cosmology is derived in modified gravity (MOG). The universe begins in the distant past in a contracting de Sitter phase, is non-singular at t = 0 and then describes approximately the standard radiation dominated solution before the time of decoupling. The spacetime in the neighborhood of t = 0 is described by Minkowski spacetime in which the Weyl curvature tensor vanishes and th...