Worldsheet theories for non-geometric string backgrounds

TL;DR

This paper develops worldsheet models using twisted doubled tori to describe non-geometric string backgrounds, clarifying conditions for Lorentz invariance and duality symmetry, and distinguishing different types of backgrounds.

Contribution

It introduces a new class of worldsheet models based on twisted doubled tori that effectively describe non-geometric string backgrounds with duality symmetry.

Findings

Twisted doubled tori provide consistent duality symmetric backgrounds.

Refined conditions for worldsheet Lorentz invariance are established.

Examples illustrate distinctions between geometric and non-geometric backgrounds.

Abstract

We show that twisted doubled tori can be used to construct a general class of worldsheet models describing non-geometric string backgrounds. By employing a first order formulation of interacting chiral bosons, we first refine the analysis on the general conditions of worldsheet Lorentz invariance and then prove that twisted doubled tori provide good duality symmetric backgrounds. Subsequently we apply our general analysis to several examples which enable us to gain new insight on the difference between geometric, locally geometric and genuine non-geometric backgrounds.