String States on AdS_3 x S^3 from the Supergroup

TL;DR

This paper analyzes the physical spectrum of string theory on AdS_3 x S^3 using the supergroup PSL(2|2), revealing a cohomological structure for the states at the first massive level and proposing its extension to higher levels.

Contribution

It provides a cohomological characterization of string states in the hybrid formulation on AdS_3 x S^3, connecting supergroup representations to the physical spectrum.

Findings

States form PSL(2|2) representations

Cohomological description at the first massive level

Partial evidence for higher-level generalization

Abstract

In the hybrid formulation of string theory on AdS_3 x S^3, the compactification-independent physical spectrum at the first massive level is determined. We find that these states transform in representations of the Lie superalgebra psl(2|2) and present a cohomological characterisation of them within the context of the PSL(2|2) WZW model. We conjecture that a similar cohomological description of the physical states also exists at higher mass levels and give partial evidence for this by comparing our results to the RNS string spectrum.