On scale-separated supersymmetric AdS$_2$ flux vacua

TL;DR

The paper demonstrates that scale-separated supersymmetric AdS$_2$ flux vacua are not achievable within controlled flux compactifications, due to the fundamental relation between the AdS$_2$ scale and BPS domain wall tension, limiting scale separation.

Contribution

It provides a general no-go argument against the existence of scale-separated supersymmetric AdS$_2$ vacua in flux compactifications, supported by both 2D supergravity and string theory models.

Findings

AdS$_2$ scale is comparable to BPS domain wall tension.

Scale separation is excluded in controlled flux compactifications.

The argument applies broadly beyond geometric scales.

Abstract

We argue that scale-separated AdS$_2$ vacua with at least two preserved supercharges cannot arise from flux compactifications in a regime of computational control. We deduce this by showing that the AdS$_2$ scale is parametrically of the same order as the tension of a fundamental BPS domain wall, which provides an upper bound on the UV cutoff. Since the latter does not need to be associated to any geometric scale, the argument excludes scale separation in a broader sense than what commonly considered. Our claim is exemplified by a bottom-up 2D supergravity analysis as well as top-down models from Type II flux compactifications.