New families of scale separated vacua

TL;DR

This paper introduces new families of flux compactification vacua in massive type IIA string theory that achieve parametric scale separation, including supersymmetric and non-supersymmetric solutions, with potential implications for string phenomenology.

Contribution

It generalizes previous constructions to new vacua with scale separation, using elliptic fibrations and flux rescaling, expanding the landscape of known string theory solutions.

Findings

Existence of infinite families of vacua with scale separation.

Stable vacua with non-universal light field spectra.

Parametric scale separation achieved via asymmetric flux rescaling.

Abstract

Massive type IIA flux compactifications of the form AdS$_4 \times X_6$, where $X_6$ admits a Calabi-Yau metric and O6-planes wrapping three-cycles, display families of vacua with parametric scale separation between the compactification scale and the AdS$_4$ radius, generated by an overall rescaling of internal four-form fluxes. For toroidal orbifolds one can perform two T-dualities and map this background to an orientifold of massless type IIA compactified on an SU(3)-structure manifold with fluxes. Via a 4d EFT analysis, we generalise this last construction and embed it into new branches of supersymmetric and non-supersymmetric vacua with similar features. We apply our results to propose new infinite families of vacua based on elliptic fibrations with metric fluxes. Parametric scale separation is achieved by an asymmetric flux rescaling which, however, in general is not a simple symmetry of the 4d equations of motion. At this level of approximation the vacua are stable but, unlike in the Calabi-Yau case, they display a non-universal mass spectrum of light fields.