A No-ghost theorem for the bosonic Nappi-Witten string
2009 (English)In: Physical Review D, ISSN 1550-7998, Vol. 80Article in journal (Refereed) Published
We prove a no-ghost theorem for a bosonic string propagating in Nappi-Witten spacetime. This is achieved in two steps. We first demonstrate unitarity for a class of NW/U(1) modules: the norm of any state which is primary with respect to a chosen timelike U(1) is non-negative. We then show that physical states - states satisfying the Virasoro constraints - in a class of modules of an affinisation of the Nappi-Witten algebra are contained in the NW/U(1) modules. Similar to the case of strings on AdS3, in order to saturate the spectrum obtained in light-cone quantization we are led to include modules with energy not bounded from below, which are related to modules with energy bounded from below by spectral flow automorphisms.
Place, publisher, year, edition, pages
2009. Vol. 80
IdentifiersURN: urn:nbn:se:uu:diva-236926DOI: 10.1103/PhysRevD.80.086003OAI: oai:DiVA.org:uu-236926DiVA: diva2:766029