Poincaré and de Sitter gauge theories of gravity with propagating torsion

We consider a gauge approach to the gravitational theory based on the local Poincaré $P_{10}$ or de Sitter $S_{10}$ groups. The $P_{10}$ gauge rotations and translations take place in the tangent spaces to the space-time manifold. We interpret the independence of matter fields from the tangent vectors as the necessity to use a nonlinear realization of the $P_{10}$ or $S_{10}$ groups thus effectively breaking the full symmetry to the Lorentz group. The Lagrangian we choose is the $S_{10}$ Yang-Mills invariant with the space-time metric expressed in terms of the translational part of the $S_{10}$ nonlinear gauge field. Various consequences of the theory are discussed, including the correspondence with general relativity, the propagating spin-connection interactions, the analogy with the chiral Higgs mechanism, instantonlike solutions, a possibility of gravitational repulsion due to the noncompactness of the Lorentz group, etc. We also analyze the quantization of the theories with torsion with special emphasis on the presence of the nonlinear realization. We stress the possibility of obtaining a renormalizable theory if the metric is not quantized but is expressed in terms of a mean value of the quantized $S_{10}$ nonlinear gauge field.