Interacting strings on AdS_3

TL;DR

This paper analyzes string theory on AdS_3 using Wakimoto free fields, deriving scattering amplitudes, vertex operators, and identifying negative norm states at the second mass level.

Contribution

It provides a detailed analysis of scattering amplitudes and vertex operators in AdS_3 string theory, revealing the presence of negative norm states at higher mass levels.

Findings

Scattering amplitudes for N tachyons are computed and analyzed.

Vertex operators for excited states are explicitly constructed.

Negative norm states are identified at the second mass level.

Abstract

We consider string theory on AdS_3 in terms of the Wakimoto free field representation. The scattering amplitudes for N unitary tachyons are analysed in the factorization limit and the poles corresponding to the mass-shell conditions for physical states are extracted. The vertex operators for excited levels are obtained from the residues and their properties are examined. Negative norm states are found at the second mass level.