T-dualities and scale-separated AdS$_3$ in massless IIA on $(X_6 \times S^1)/\mathbb{Z}_2$

TL;DR

The paper constructs and analyzes new scale-separated AdS3 flux vacua in massless type IIA string theory, using T-duality from massive solutions on G2 orbifolds, with potential uplift to eleven-dimensional supergravity.

Contribution

It presents novel scale-separated AdS3 solutions in massless IIA, derived via T-duality from massive backgrounds, and explores their properties and uplift possibilities.

Findings

Constructed new scale-separated AdS3 flux vacua in massless IIA.

Identified families of solutions with large radii, scale separation, and strong coupling.

Derived the superpotential and analyzed the uplift to eleven-dimensional supergravity.

Abstract

Motivated by the question of whether scale-separated AdS$_3$ flux vacua arising from G$_2$ compactifications admit an uplift to eleven-dimensional supergravity, we construct scale-separated AdS$_3$ flux vacua in massless type IIA with only O6-planes. We first present new scale-separated solutions in massive type IIA on a G$_2$ holonomy toroidal orbifold with four smeared O6-planes, analyze their properties, and then perform a double T-duality to obtain the corresponding massless backgrounds. In the dual frame, the internal space is locally given by a six-dimensional quotient space $X_6$ with an $\mathrm{SU}(3)$ structure of Iwasawa type times an untwisted circle $S^1$, while globally it is further modded out by a non-trivial $\mathbb{Z}_2$ quotient inherited from the G$_2$ orbifold action. Finally, we use T-duality to derive the corresponding superpotential in massless type IIA and identify parametrically classical, scale-separated families of solutions, as well as a family with parametrically large radii, scale separation, and strong coupling, thus allowing for an uplift to eleven-dimensional supergravity.