Conformal Compensators and Manifest Type IIB S-Duality

TL;DR

This paper demonstrates how conformal compensator superfields in N=2 D=4 supergravity facilitate a linear representation of Type IIB S-duality, preserving invariance in the superspace action and enabling the addition of a Fradkin-Tseytlin term.

Contribution

It introduces a novel formulation of Type IIB S-duality as a linear rotation using conformal compensators, maintaining manifest invariance in the superspace action.

Findings

Type IIB S-duality expressed as a linear rotation of superfields.

Superspace action remains invariant under S-duality transformations.

Inclusion of Fradkin-Tseytlin term enhances SL(2,Z) covariance.

Abstract

Using the conformal compensator superfields of N=2 D=4 supergravity, the Type IIB S-duality transformations are expressed as a linear rotation which mixes the compensator and matter superfields. The classical superspace action for D=4 compactifications of Type IIB supergravity is manifestly invariant under this transformation. Furthermore, the introduction of conformal compensators allows a Fradkin-Tseytlin term to be added to the manifestly SL(2,Z)-covariant sigma model action of Townsend and Cederwall.