A Class of String Backgrounds as a Semiclassical Limit of WZW Models

TL;DR

This paper explores a new class of string backgrounds derived from non semi-simple groups as a large level limit of WZW models, including the Nappi-Witten background, with implications for understanding semiclassical limits.

Contribution

It introduces a novel class of string backgrounds from non semi-simple groups as a semiclassical limit of WZW models, expanding the landscape of solvable string theories.

Findings

Identifies a class of backgrounds with integer Virasoro central charge.

Includes the Nappi-Witten background as a special case.

Establishes a connection between non semi-simple groups and semiclassical string limits.

Abstract

A class of string backgrounds associated with non semi-simple groups is obtained as a special large level limit of ordinary WZW models. The models have an integer Virasoro central charge and they include the background recently studied by Nappi and Witten.