Speaker: Adrià Delhom I LatorrePlace: 241 Nicholson
Date: Wednesday Nov 20th
Time: 13:30
Title: Curvature-based Metric-affine gravity
Abstract: I will give an overview of metric-affine gravity theories, focusing in
those with actions built with the Ricci tensor, trying to emphasize the
phenomenological aspects of these theories that are similar to those
encountered in quantum gravity theories.
First, I will review the different frameworks that fall within
metric-affine gravity (teleparallel, gauge gravity, etc.). Focusing on
actions built upon curvature tensors (curvature-based), I will then
explain why low-curvature modifications to GR, that could
explain the accelerated expansion, are ruled out by experiments. Then I
will show why metric-affine higher order curvature theories can be free
from ghosts and the role played by projective symmetry on this. After
that, I will give some results involving black
hole like objects that arise naturally in several metric-affine models
are described by non-singular spacetimes (in the sense of geodeticall
completeness). I will also present some bouncing cosmological models
within these theories and how the LQC dynamics
can be mimicked by an f(R) theory. Finally, I will show how in some
curvature-based metric-affine gravity the matter sector develops
non-linear interactions that can be used to constrain these theories.
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