Nonlinear 4D conformal gauge spacetime symmetry

Abstract

The nonlinear local theory of the 4D conformal spacetime group is presented. Effective theories of gravity quadratic in curvatures may be viewed as nonlinear realizations of this group. We find that in the absence of torsion and under very general assumptions derived from the structure of the algebra, the symmetry takes the form of the simpler Weyl scale invariance and the resulting theory is Einstein's gravity with, generally, a cosmological constant.