The diagonal cosets of the Heisenberg group

D'APPOLLONIO, GIUSEPPE;QUELLA T.

2008-01-01

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Abstract

In this paper we study the diagonal cosets of the non-compact H-4 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.