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 type of string solitons (0-branes) as the quantum phase space of a point particle. The sigma-model is slightly non critical, and therefore one should dress it with a Liouville mode. Quantization is achieved by summing over world-sheet genera (in the pinched approximation). To leading order in the coupling constant expansion, the quantization reproduces the usual quantum mechanical commutator. We attempt to go beyond leading order and we reproduce the generalized string uncertainty principle.