Klein-Gordon-Wheeler-DeWitt-Schroedinger Equation

Understand

We start from the Einstein-Hilbert action for the gravitational field in the presence of a "point particle" source, and cast the action into the corresponding phase space form.

• The dynamical variables of such a system satisfy the point particle mass shell constraint, the Hamilton and the momentum constraints of the canonical gravity.
• In the quantized theory, those constraints become operators that annihilate a state.
• A state can be represented by a wave functional $\Psi$ that simultaneously satisfies the Klein-Gordon and the Wheeler-DeWitt-Schr\"odinger equation.