The ‘‘tunneling’’ approach to quantum cosmology is applied to a perturbative superspace model in which the inhomogeneous modes of the gravitational and scalar fields are treated as linear perturbations. It is shown that in this approach the wave function of the Universe is uniquely determined by the boundary conditions. It describes a universe nucleating as a de Sitter space with quantum fields in de Sitter-invariant vacuum states.

• Received 15 October 1987

DOI:https://doi.org/10.1103/PhysRevD.37.898