Short-distance space-time structure and black holes in string theory: A short review of the present status

We briefly review the present status of string theory From the viewpoint of its implications on the short-distance space-time structure and black hole physics. Special emphases are given on two closely related issues in recen t developments towards nonperturbative string theory, namely, the role of t he space-time uncertainty relation as a qualitative but universal character ization of the short-distance structure of string theory and the microscopi c formulation of black-hole entropies. We will also suggest that the space- time uncertainty relation can be an underlying principle for the holographi c property of M theory, by showing that the space-time uncertainty relation naturally explains the UV/IR relation used in a recent derivation of the h olographic bound for D3 brane by Susskind and Witten. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.