A Lorentz invariant doubled worldsheet theory

TL;DR

This paper introduces a Lorentz invariant doubled worldsheet theory that makes T-duality covariance explicit and can describe both geometric and non-geometric string backgrounds.

Contribution

It presents a Lorentz invariant formulation of Tseytlin's doubled worldsheet theory, incorporating non-geometric backgrounds and fractional O(D,D) transformations.

Findings

The theory is derived as a gauge-fixed version of Buscher's gauging.

It naturally accounts for fractional linear O(D,D) transformations.

It encodes geometric and non-geometric fluxes in the doubled tensor field strength.

Abstract

We propose a Lorentz invariant version of Tseytlin's doubled worldsheet theory that makes T-duality covariance of the string manifest. This theory can be derived as a gauge fixed version of Buscher's gauging procedure, in which the left-over gauge field component acts as a Lagrange multiplier. This description can naturally account for fractional linear O(D,D) transformations of the metric and b-field. It is capable of describing non-geometric backgrounds; geometric and non-geometric fluxes are encoded in the doubled anti-symmetric tensor field strength.