  Canonical quantization of spherically symmetric initial data which is
appropriate to classical interior black hole solutions in four dimensions is
carried out and solved exactly without gauge fixing the remaining kinematic
Gauss Law constraint. The resultant mini-superspace manifold and arena for
quantum geometrodynamics is two-dimensional, of signature (+, -), non-singular,
and can in fact be identified precisely with the first Rindler wedge. The
associated Wheeler-DeWitt equation with evolution in intrinsic superspace time
can be formulated as a free massive Klein-Gordon equation; and the
Hamilton-Jacobi semiclassical limit of plane wave solutions can be matched
precisely to the interiors of Schwarzschild black holes. Furthermore, classical
black hole horizons and singularities correspond to the boundaries of the
Rindler wedge. Exact wavefunctions of the first-order-in-superspace intrinsic
time Dirac equation are also considered. Precise correspondence between
Schwarzschild black holes and free particle mechanics in superspace is noted.
Another intriguing observation is that, despite the presence of classical
horizons and singularities, hermiticity of the Dirac hamiltonian operator for
the mini-superspace, and thus unitarity of the quantum theory, is equivalent to
an appropriate boundary condition which must be satisfied by the quantum
states. This boundary condition holds for quite generic quantum wavepackets of
energy eigenstates, but fails for the usual Rindler fermion modes which are
precisely eigenstates with zero uncertainty in energy.
