The String Measure and Spectral Flow of Critical N=2 Strings

摘要

The general structure of N=2 moduli space at arbitrary genus and instantonnumber is investigated. The N=2 NSR string measure is calculated, yieldingpicture- and U(1) ghost number-changing operator insertions. An explicitformula for the spectral flow operator acting on vertex operators is given, andits effect on N=2 string amplitudes is discussed.