Hamiltonian analysis of Poincaré gauge theory scalar modes

The Hamiltonian constraint formalism is used to obtain the first explicit complete analysis of nontrivial viable dynamic modes for the Poincaré gauge theory of gravity. Two modes with propagating spin-zero torsion are analyzed. The explicit form of the Hamiltonian is presented. All constraints are obtained and classified. The Lagrange multipliers are derived. It is shown that a massive spin-0^- mode has normal dynamical propagation but the associated massless 0^- is pure gauge. The spin-0⁺ mode investigated here is also viable in general. Both modes exhibit a simple type of "constraint bifurcation" for certain special field/parameter values.