Double Field Theory of Type II Strings

TL;DR

This paper employs double field theory to unify the low energy descriptions of type IIA and IIB superstrings, incorporating Ramond-Ramond potentials as spinors and proposing a new fundamental gravitational variable.

Contribution

It introduces a novel formulation where Ramond-Ramond potentials are spinor representations and suggests a new fundamental gravitational variable within the double field theory framework.

Findings

Unified description of IIA and IIB superstring limits

Ramond-Ramond potentials as spinors of O(D,D)

Proposal of a new fundamental gravitational variable

Abstract

We use double field theory to give a unified description of the low energy limits of type IIA and type IIB superstrings. The Ramond-Ramond potentials fit into spinor representations of the duality group O(D,D) and field-strengths are obtained by acting with the Dirac operator on the potentials. The action, supplemented by a Spin^+(D,D)-covariant self-duality condition on field strengths, reduces to the IIA and IIB theories in different frames. As usual, the NS-NS gravitational variables are described through the generalized metric. Our work suggests that the fundamental gravitational variable is a hermitian element of the group Spin(D,D) whose natural projection to O(D,D) gives the generalized metric.