Toroidal Orientifolds in IIA with General NS-NS Fluxes

Understand

Type IIA toroidal orientifolds offer a promising toolkit for model builders, especially when one includes not only the usual fluxes from NS-NS and R-R field strengths, but also fluxes that are T-dual to the NS-NS three-form flux.

• These new ingredients are known as metric fluxes and non-geometric fluxes, and can help stabilize moduli or can lead to other new features.
• In this paper we study two approaches to these constructions, by effective field theory or by toroidal fibers twisted over a toroidal base.
• Each approach leads us to important observations, in particular the presence of D-terms in the four-dimensional effective potential in some cases, and a more subtle treatment of the quantization of the general NS-NS fluxes.