Graceful exit in quantum string cosmology

M. Gasperini, J. Maharana, G. Veneziano

Submitted on 16 February 1996


We write an O(d,d)-covariant Wheeler-De Witt equation in the (d2+1)-dimensional minisuperspace of low-energy cosmological string backgrounds. We discuss explicit examples of transitions between two duality-related cosmological phases, and we find a finite quantum transition probability even when the two phases are classically separated by a curvature singularity. This quantum approach is completely free from operator ordering ambiguities as a consequence of the duality symmetries of the string effective action.


Comment: 16 pages, LATEX. A complete collection of papers and references on the pre-big-bang scenario in string cosmology is available at

Subjects: High Energy Physics - Theory; Astrophysics; General Relativity and Quantum Cosmology