2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/349002D $R^2$ quantum gravity in infinitely large invariant volume is considered. In weak coupling limit the dynamics is reduced to quantum mechanics of a single degree of freedom. The correspondent two - point Green function is calculated explicitly in Gaussian approximation.Accepted for publication in Phys. Lett. BGeneral Relativity and Quantum CosmologyHigh Energy Physics - LatticeHigh Energy Physics - Theorytext