Hamiltonian analysis of nonlocal F(R) gravity models

Effective Nonlocal Euclidean Gravity

A nonlocal form of the effective gravitational action could cure the unboundedness of euclidean gravity with Einstein action. On sub-horizon length scales the modified gravitational field equations seem compatible with all present tests of general relativity and post-Newtonian gravity. They induce a difference in the effective Newton’s constant between regions of space with vanishing or nonvani...

Hamiltonian spinfoam gravity

Hamiltonian analysis of n-dimensional Palatini gravity with matter

We consider the Palatini formalism of gravity with cosmological constant Λ coupled to a scalar field φ in n-dimensions. The n-dimensional Einstein equations with Λ can be derived by the variation of the coupled Palatini action provided n > 2. The Hamiltonian analysis of the coupled action is carried out by a 1 + (n− 1) decomposition of the spacetime. It turns out that both Palatini action and H...

A New Model of Nonlocal Modified Gravity

In spite of the great successes of General Relativity (GR) it has not got the status of a complete theory of gravity. To modify GR there are motivations coming from its quantum aspects, string theory, astrophysics and cosmology. For example, cosmological solutions of GR contain Big Bang singularity, and Dark Energy as a cause for accelerated expansion of the Universe. This initial cosmological ...

Translation invariant time-dependent massive gravity: Hamiltonian analysis

The canonical structure of the massive gravity in the first order moving frame formalism is studied. We work in the simplified context of translation invariant fields, with mass terms given by general non-derivative interactions, invariant under the diagonal Lorentz group, depending on the moving frame as well as a fixed reference frame. We prove that the only mass terms which give 5 propagatin...