SCALE FACTOR DUALITY FOR CLASSICAL AND QUANTUM STRINGS

Duality under inversion of the cosmological scale factor is discussed both for the classical motion of strings in cosmological backgrounds and for genus zero, low energy effective actions. The string-modified, Einstein-Friedmann equations are then shown to possess physically-inequivalent, duality-related solutions which generically describe the "decay" of an initial, perturbative, flat D = 10 superstring vacuum towards a more interesting strong-coupling state through an appealing pre-big-bang cosmological scenario.