Quantum gravity at spatial infinity?

Abstract

The nonquantum treatment of the gravitational field equations at spatial infinity yields formal solutions, one-half of which lend themselves readily to a physical interpretation in terms of gravitational fields in space-time, whereas the other half involve unacceptable singularities when extended to approach light-like infinity. The quantization of the field equations at spatial infinity formally is straightforward, the Hamiltonian being purely quadratic in the canonical field variables, but the discard of half of the classical solutions produces serious difficulties in the quantum version, for which a possible remedy is tentatively proposed.