Modular Invariance of Strings on PP-Waves with RR-flux

TL;DR

This paper demonstrates the modular invariance of string theories on pp-wave backgrounds with RR-flux, analyzing their spectra and dual gauge theories, including supersymmetry aspects and orbifold constructions.

Contribution

It explicitly shows modular invariance of one-loop partition functions for pp-waves with RR-flux and explores spectra and supersymmetry in related orbifold theories.

Findings

Partition functions are modular invariant despite mass terms.

Spectrum of type 0B theory on pp-wave identified.

Supersymmetry enhancement observed in non-supersymmetric orbifolds.

Abstract

We study the modular invariance of strings on pp-waves with RR-flux. We explicitly show that the one-loop partition functions of the maximally supersymmetric pp-waves and their orbifolds can be modular invariant in spite of the mass terms in the light-cone gauge. From this viewpoint, we also determine the spectrum of type 0B theory on pp-wave and discuss its gauge theory dual. Furthermore, we investigate the spectrum of a non-supersymmetric orbifold and point out its supersymmetry enhancement in the Penrose limit.