QUANTUM PHASE-SPACE FROM STRING SOLITONS

In this paper we view the sigma-model couplings of appropriate vertex operators describing the interaction of string matter with a certain t ype of string soliton (O-brane) as the quantum phase space of a point particle. The a model is slightly noncritical and, therefore, one shou ld dress it with a Liouville mode. Quantization is achieved by summing over world-sheet genera (in the pinched approximation). To leading or der in the coupling-constant expansion, the quantization reproduces th e usual quantum-mechanical commutator. We attempt to go beyond leading order, and we reproduce the generalized string uncertainty principle.