Partition Functions for BPS States of the Non-Critical E_8 String
arXiv:hep-th/9707149
Abstract
We consider the BPS states of the non-critical string wound around one of the circles of a toroidal compactification to four dimensions. These states are indexed by their momenta and winding numbers. We find explicit expressions, , for the momentum partition functions for the states with winding number . The are given in terms of modular forms. We give a simple algorithm for generating the , and we show that they satisfy a recurrence relation that is reminiscent of the holomorphic anomaly equations of Kodaira-Spencer theory.
17 pages, harvmac(b)