Poincare gauge gravity from nonmetric gravity

Abstract

We consider general linear gauge theory, with independent solder form and connection. These spaces have both torsion and nonmetricity. We show that the Cartan structure equations together with the defining equation for nonmetricity allow the mixed symmetry components of nonmetricity to be absorbed into an altered torsion tensor. Field redefinitions reduce the structure equations to those of Poincare gauge theory, with local Lorentz symmetry and metric compatibility.

In order to allow recovery the original torsion and nonmetric fields, we replace the definition of nonmetricity by an additional structure equation and demand integrability of the extended system. We show that the maximal Lie algebra compatible with the enlarged set is isomorphic to the conformal Lie algebra. From this Lorentzian conformal geometry, we establish that the difference between the field strength of special conformal transformations and the torsion and is given by the mixed symmetry nonmetricity of an equivalent asymmetric system.