On the DGKT brane dual and its decoupling

TL;DR

This paper constructs a ten-dimensional brane geometry for DGKT AdS vacua, demonstrating that the brane worldvolume theory decouples from the bulk, supporting the existence of a holographic dual for scale-separated AdS vacua.

Contribution

It provides a novel flux-backtracking approach to model DGKT vacua and analyzes mode decoupling, offering evidence for holography in scale-separated AdS backgrounds.

Findings

Modes near the branes are infinitely redshifted, indicating decoupling.

Graviton fluctuations reveal an infinite potential barrier near the branes.

Results support the possibility of a holographic dual for DGKT vacua.

Abstract

It is not understood whether scale-separated AdS vacua in string theory admit a holographic dual. A well-known class of such vacua is provided by the DGKT solutions of massive type IIA string theory, where scale separation arises from large fluxes. In this work, we construct a ten-dimensional brane geometry whose near-horizon limit reproduces the DGKT vacua, using a flux-backtracking approach combined with intersecting D4-brane stacks dual to the unbounded flux sector. We then use this setup to test whether the brane worldvolume theory decouples from the bulk. Modes localised near the branes, deep in the AdS throat, are found to be infinitely redshifted with respect to asymptotic observers. Moreover, an analysis of graviton fluctuations shows the presence of an infinite potential barrier near the branes, providing a direct indication of decoupling. We conclude by comparing these results with recent arguments against decoupling in scale-separated AdS vacua, which focus on the asymptotic region where modes are blueshifted.