Why do we live in a Riemannian space time ?
Abstract
We start from the pure EinsteinHilbert action in Metric Affine Gravity, with the orthonormal metric. We get an effective LeviCivita Dilaton gravity theory in which the Dilaton field is related to the scaling of the gravitational coupling. When the Weyl symmetry is broken the resulting EinsteinHilbert term is equivalent to the LeviCivita one, using the projective invariance of the model, the nonmetricity and torsion may be removed, so that we get a theory perfectly equivalent to general relativity. This may explain why low energy gravity is described by a Riemannian connection.
 Publication:

arXiv eprints
 Pub Date:
 October 1999
 arXiv:
 arXiv:grqc/9910110
 Bibcode:
 1999gr.qc....10110S
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 9 pages, Latex