The diagonal cosets of the Heisenberg group

TL;DR

This paper provides an exact world-sheet description of diagonal cosets of the H4 WZW model, exploring their interpolation between singular and non-singular plane waves and analyzing their spectra.

Contribution

It generalizes previous work to include non-maximally symmetric gravitational plane waves with NS fluxes, offering new insights into their sigma-models and spectra.

Findings

Models interpolate smoothly between singular and non-singular waves

Spectrum of all models derived and analyzed

Representation theory of the coset chiral algebra explored

Abstract

In this paper we study the diagonal cosets of the non-compact H4 WZW model. Generalising earlier work by Antoniadis and Obers, we provide an exact world-sheet description for several families of non-maximally symmetric gravitational plane waves with background NS fluxes. We show that the sigma-models that correspond to an asymmetric action of the gauge group smoothly interpolate between singular and non-singular plane waves. We also analyse the representations of the coset chiral algebra and derive the spectrum of all the models.