A Class of Non-singular Gravi-dilaton Backgrounds

We present a class of static, spherically symmetric, non-singular solutions of the tree-level string effective action, truncated to first order in α ′. In the string frame the solutions approach asymptotically (at r → 0 and r → ∞) two different anti-de Sitter configurations, thus interpolating between two maximally symmetric states of different constant curvature. The radial-dependent dilaton defines a string coupling which is everywhere finite, with a peak value that can be chosen arbitrarily small so as to neglect quantum-loop corrections. This example stresses the possible importance of finite-size α ′ corrections, typical of string theory, in avoiding space-time singularities. 1 This essay received an " Honorable Mention " from the Gravity Research Foundation, 1997 — Ed.