String Theory, Scale Relativity and the Generalized Uncertainty Principle

Extensions (modi cations) of the Heisenberg Uncertainty principle are derived within the framework of the theory of Special Scale-Relativity proposed by Nottale. In particular, generalizations of the Stringy Uncertainty Principle are obtained where the size of the strings is bounded by the Planck scale and the size of the Universe. Based on the fractal structures inherent with two dimensional Quantum Gravity, which has attracted considerable interest recently, we conjecture that the underlying fundamental principle behind String theory should be based on an extension of the Scale Relativity principle where both dynamics as well as scales are incorporated in the same footing.