Conveners
[MG] Modifications of gravity
- Jose Beltran Jimenez (Universite d'Aix-Marseille)
[MG] Modifications of gravity
- Jose Beltran Jimenez (Universite d'Aix-Marseille)
The discovery, in 1998, that the Universe is currently undergoing an
accelerated expansion is one of the greatest milestones in all physics.
Naturally, over the last 17 years, many proposals to explain this
evolution have been brought forward. Most ideas involve scalar field
dark energy or extensions of Einstein's gravity. These proposals are
essentially phenomenological without any...
We consider a massive vector field with derivative interactions that propagates only the 3 desired polarizations (besides two tensor polarizations from gravity) with second-order equations of motion in curved space-time. The cosmological implications of such generalized Proca theories are investigated for both the background and the linear perturbation by taking into account the Lagrangian up...
I will introduce a geometrical framework with a connection that is fully determined by a vector field as a generalization of Weyl geometry. Within these geometries, it is possible to formulate gravitational theories that lead to interesting vector-tensor theories with non-minimal couplings and derivative self-interactions such that the vector only propagates the 3 polarizations corresponding...
Cosmology papers arXiv:1003.1686, 1006.1246, 1112.5308, 1411.1947, 1511.03933;
PPN papers arXiv:1309.0031, 1607.?????.
We derive a formula for the post-Newtonian parameter $\gamma$ in $f(R)$ gravity in a straightforward manner without using a scalar-tensor representation or the transformation to the Einstein frame.
The post-Newtonian parameters, defined in the parametrized post-Newtonian formalism, have been used in placing observational constraints on modified theories of gravity with local gravity tests....
ABSTRACT: We show that a significant correlation (up to 5σ) emerges between the bulge index, defined to be larger for a larger bulge/disk ratio, in spiral galaxies with similar luminosities in the Galaxy Zoo 2 of the Sloan Digital Sky Survey and the number of tidal-dwarf galaxies in the catalog by Kaviraj et al. In the standard cold or warm dark matter cosmological models, the number of...
