A minimal model of Lorentz gauge gravity with dynamical torsion

Understand

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.