The massless string spectrum on AdS_3 x S^3 from the supergroup

TL;DR

This paper analyzes the massless string spectrum on AdS_3 x S^3 using the supergroup PSL(2|2) WZW model, confirming it matches supergravity predictions and providing detailed insights into the underlying supergroup structure.

Contribution

It offers a detailed description of the supergroup WZW model and explicitly determines the BRST-cohomology for massless states in the hybrid string formulation.

Findings

Spectrum matches supergravity predictions

Explicit BRST-cohomology for massless states derived

Detailed supergroup WZW model description provided

Abstract

String theory on AdS_3 x S^3 is studied in the hybrid formulation. We give a detailed description of the PSL(2|2) supergroup WZW model that underlies the background with pure NS-NS flux, and determine the BRST-cohomology corresponding to the massless string states. The resulting spectrum is shown to match exactly with the expected supergravity answer, including the sectors with small KK momentum on the sphere.