Speaker
Description
The polynomial affine gravity is an alternative model to describe gravitational interactions using the affine connection as the sole mediator. The action is built using a sort of dimensional analysis technique and preserving the invariance under diffeomorphisms. Interestingly, the coupling constants are dimensionless, which is desirable from a quantum field stand point. In $3+1$ dimensions the field equations in the torsion free sector contain Einstein's vacuum equations, moreover, it is possible interpret the symmetric part of the Ricci tensor or a special combination of the product of two torsion tensors as an emergent metric in this model. Similar analysis can be done in $2+1$ dimensions. Therefore, starting from a purely affine geometrical model, we can obtain a metric tensor, and consequently define physical quantities such as the redshift, classification of space-null-time like self-parallel curves, providing a way to differentiate trajectories of massive and massless particles.
