Black Hole Condensation and Duality in String Theory

Abstract

The classical, four-dimensional theories derived by Calabi-Yau compactification of string theory bear a striking resemblance to the real world [1]. However, these classical theories are beset by several serious difficulties:

• 1. There are too many of them. This is aesthetically displeasing because a unified theory should be unique. It also entails a loss of predictive power.

• 2. The theory breaks down and develops naked singularities at certain “conifold” points in the moduli space of the massless four-dimensional scalar fields [2].