Abstract

In the last decade, a framework in which string dualities are implemented at the supergravity level has been developed, i.e., the so-called embedding tensor formalism. However, the connection between this formalism and string theory realisations remains still obscure since most of the supergravities obtained by using the embedding tensor formalism correspond to very exotic (non-)geometries in the string side.

In this talk we consider type II flux backgrounds compatible with the absence of brane sources, and construct their explicit embedding into maximal D=4 supergravity. This enables us to investigate the critical points, mass spectra and gauge groups of such “exceptional” backgrounds in a systematic way. We will chart the landscape of vacua in some specific setups which are relevant from the string theory viewpoint and discuss the issues of stability and supersymmetry at those vacuum solutions. Finally we will point towards some natural extensions of the results.