Duality phases and halved maximal D=4 supergravity

TL;DR

This paper investigates specific gaugings of N=8 supergravity using duality angles, revealing that only three semisimple gaugings can be embedded into N=8, with some exhibiting unstable scalar potential extrema.

Contribution

It demonstrates that only three semisimple N=4 gaugings with duality angles can be embedded into N=8 supergravity, clarifying the limitations of such deformations.

Findings

Only three semisimple gaugings can be embedded into N=8 supergravity.

Scalar potentials for two gaugings have extrema at the origin.

The extrema are unstable under scalar fluctuations.

Abstract

The duality angles deformation developed by de Roo and Wagemans within the context of N=4 gauged supergravity is used in order to study certain classes of gaugings of N=8 supergravity, namely, those that are consistent when halving the maximal D=4 theory. After reviewing the truncation process from N=8 to N=4 supergravity in terms of the embedding tensor formalism, the de Roo-Wagemans phases method is implemented for solving the resulting constraints on the gauging parameters by means of the Schon-Weidner ansatz. In contrast with the twenty semisimple N=4 gaugings admitting more than a single SL(2) angle deforming their decompositions reported in the literature, it is proven that only three of them can be embedded back into the N=8 theory. The scalar potential derived for only two of these gauge groups exhibits an extremum in the origin of the scalar manifold. These extrema are not stable under fluctuations of all the scalar fields.