Green-Schwarz superstring on doubled-yet-gauged spacetime

TL;DR

This paper develops a Green-Schwarz superstring action in doubled-yet-gauged spacetime that maintains T-duality and Lorentz symmetry, unifying various string theories and backgrounds within a single formalism.

Contribution

It introduces a novel world-sheet action for superstrings in doubled spacetime, incorporating gauge symmetries and dualities, and reduces to the standard action in flat backgrounds.

Findings

The action exhibits $ ext{O}(10,10)$ T-duality and Lorentz symmetry.

It reduces to the original Green-Schwarz action after gauge fixing.

The formalism distinguishes IIA, IIB, and non-Riemannian backgrounds.

Abstract

We construct a world-sheet action for Green-Schwarz superstring in terms of doubled-yet-gauged spacetime coordinates. For an arbitrarily curved NS-NS background, the action possesses $\mathbf{O}(10,10)$ T-duality, $\mathbf{Spin}(1,9)\times\mathbf{Spin}(9,1)$ Lorentz symmetry, coordinate gauge symmetry, spacetime doubled-yet-gauged diffeomorphisms, world-sheet diffeomorphisms and Weyl symmetry. Further, restricted to flat backgrounds, it enjoys maximal spacetime supersymmetry and kappa-symmetry. After the auxiliary coordinate gauge symmetry potential being integrated out, our action can consistently reduce to the original undoubled Green-Schwarz action. Thanks to the twofold spin groups, the action is unique: it is specific choices of the NS-NS backgrounds that distinguish IIA or IIB, as well as lead to non-Riemannian or non-relativistic superstring a la Gomis-Ooguri which might deserve the nomenclature, type IIC.