The No-ghost Theorem for AdS_3 and the Stringy Exclusion Principle

TL;DR

This paper provides a complete proof of the No-ghost Theorem for string theories on AdS_3 and demonstrates that the spin restriction aligns with the stringy exclusion principle, clarifying spectrum constraints.

Contribution

It offers the first complete proof of the No-ghost Theorem for AdS_3 string theories and links the spin restriction to the stringy exclusion principle.

Findings

Proof of the No-ghost Theorem for AdS_3 string theories

Identification of spin restrictions with the stringy exclusion principle

Clarification of ghost-free spectrum conditions

Abstract

A complete proof of the No-ghost Theorem for bosonic and fermionic string theories on AdS_3, or the group manifold of SU(1,1), is given. It is then shown that the restriction on the spin (in terms of the level) that is necessary to obtain a ghost-free spectrum corresponds to the stringy exclusion principle of Maldacena and Strominger.