Scale Factor Duality For Classical And Quantum Strings

Abstract

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. CERN--TH-6077/91 April 1 INTRODUCTION Undoubtedly, one of the deepest quantum symmetries of string theory is (target space) duality. In its simplest form [1], duality says that a (closed) string moving on a circle of radius R is equivalent to one which moves on a circle of radius 2 s =R where 2 s = 2ff 0 ¯ h is the fundamental length parameter (Planck constant) of string theory. Duality has been extended to more complicated situations [2, 3, 4] and is more general..