Heterotic non-linear sigma models with anti-de Sitter target spaces

TL;DR

This paper computes the beta function of heterotic non-linear sigma models with AdS target spaces using a 1/D expansion, providing insights into the spacetime effective action and conformal invariance conditions.

Contribution

It introduces a 1/D expansion method to calculate the beta function for heterotic sigma models with AdS target spaces, extending previous work to all orders in ' and second order in 1/D.

Findings

Beta function calculated up to order 1/D^2 and all orders in '

Identification of conditions for conformal invariance with AdS target space

Calculation of critical exponents and consistency checks

Abstract

We calculate the beta function of non-linear sigma models with S^{D+1} and AdS_{D+1} target spaces in a 1/D expansion up to order 1/D^2 and to all orders in \alpha'. This beta function encodes partial information about the spacetime effective action for the heterotic string to all orders in \alpha'. We argue that a zero of the beta function, corresponding to a worldsheet CFT with AdS_{D+1} target space, arises from competition between the one-loop and higher-loop terms, similarly to the bosonic and supersymmetric cases studied previously in hep-th/0512355. Various critical exponents of the non-linear sigma model are calculated, and checks of the calculation are presented.