Classical/Quantum Duality
arXiv:hep-th/9410210
Abstract
String theory requires two kinds of loop expansion: classical worldsheet loops with expansion parameter where is a modulus field, and quantum spacetime loops with expansion parameter where is the dilaton field. Four-dimensional string/string duality (a corollary of ten-dimensional string/fivebrane duality) interchanges the roles of and and hence interchanges classical and quantum.
5 pages latex, NI-94-016, Typographical errors corrected