AdS vacua with scale separation from IIB supergravity

TL;DR

This work constructs and analyzes four-dimensional AdS vacua with $ obreak{ ext{N}=1 }$ supersymmetry in type IIB supergravity using smeared O5/O7 planes and a rigid $ ext{SU}(2)$ internal structure expressed via pure spinors. By specializing to left-invariant forms on coset and nilmanifold geometries, the authors derive a tractable set of ten-dimensional SUSY conditions, present explicit solutions, and investigate the possibility of scale separation at tree level. They find explicit IIB AdS$_4$ backgrounds in nilmanifolds (and some cosets) that exhibit tunable weak coupling and large volume, with scale separation realized in certain cases, while highlighting no-go trends for sourceless backgrounds. The results extend the landscape of tree-level AdS vacua with scale separation beyond massive IIA and illuminate the role of O5/O7 sources and SU(2) structure in achieving controlled 4D holographic settings, while raising questions about localisation and warping effects in fully consistent setups.

Abstract

Only two kinds of compactification are known that lead to four-dimensional supersymmetric AdS vacua with moduli stabilisation and separation of scales at tree-level. The most studied ones are compactifications of massive IIA supergravity on SU(3) structures with smeared O6 planes, for which a general ten-dimensional expression for the solution in terms of the SU(3) structure was found. Less studied are compactifications of IIB supergravity with smeared O5/O7 planes. In this paper we derive a general ten-dimensional expression for the smeared O5/O7 solutions in terms of SU(2) structures. For a specific choice of orientifold projections, we recover the known examples and we also provide new explicit solutions.