An alternative to anti-branes and O-planes?

In this paper we consider type IIA compactifications in the isotropic Z2 × Z2 orbifold with a flux-induced perturbative superpotential combined with non-perturbative effects. Without requiring the presence of O-planes, and simply having D6-branes as local sources, we demonstrate the existence of de Sitter (dS) critical points, where the non perturbative contributions to the cosmological constant have negligible size. We note, however, that these solutions generically have tachyons. By means of a more systematic search, we are able to find two examples of stable dS vacua with no need for anti-branes or O-planes, which, however, exhibit important non perturbative corrections. The examples that we present turn out to remain stable even after opening up the fourteen non-isotropic moduli.