  A new Lorentz gauge gravity model with R^2-type Lagrangian is proposed. In
the absence of classical torsion the model admits a topological phase with an
arbitrary metric. We analyze the equations of motion in constant curvature
space-time background using the Lagrange formalism and demonstrate that the
model possesses a minimal set of dynamic degrees of freedom for the torsion.
Surprisingly, the number of torsion dynamic degrees of freedom equals the
number of physical degrees of freedom for the metric tensor. An interesting
feature of the model is that the spin two mode of torsion becomes dynamical
essentially due to the non-linear structure of the theory. We perform covariant
one-loop quantization of the model for a special case of constant curvature
space-time background. We treat the contortion as a quantum field variable
whereas the metric tensor is kept as a classical object. We discuss a possible
mechanism of an emergent Einstein gravity as a part of the effective theory
induced due to quantum dynamics of torsion.
