Stringy Unification of Type IIA and IIB Supergravities under N=2 D=10 Supersymmetric Double Field Theory

TL;DR

This paper constructs a unified type II supergravity theory in 10 dimensions using supersymmetric double field theory, revealing that IIA and IIB are solutions of the same underlying framework with manifest T-duality symmetry.

Contribution

It presents the full-order fermionic supersymmetric double field theory that unifies type IIA and IIB supergravities in a covariant manner under T-duality.

Findings

Type IIA and IIB are solutions, not separate theories.

The theory maintains manifest T-duality and local Lorentz symmetry.

The construction is unique and fully supersymmetric to all fermion orders.

Abstract

To the full order in fermions, we construct D=10 type II supersymmetric double field theory. We spell the precise N=2 supersymmetry transformation rules as for 32 supercharges. The constructed action unifies type IIA and IIB supergravities in a manifestly covariant manner with respect to O(10,10) T-duality and a pair of local Lorentz groups, or Spin(1,9) \times Spin(9,1), besides the usual general covariance of supergravities or the generalized diffeomorphism. While the theory is unique, the solutions are twofold. Type IIA and IIB supergravities are identified as two different types of solutions rather than two different theories.