(12.06.) Relative Quantum Gravity: Localized Gravity and the Swampland
Jesus Huertas (IFT Madrid)
12.06.2025 at 16:15
We perform a systematic study of the applicability of swampland constraints to theories of localized gravity. We find that these gravity theories can violate swampland constraints, but can be reconciled with them when coupled to a higher-dimensional gravity theory. They realize what we call relative quantum gravity: to become consistent at the quantum level, these gravity theories must be defined as relative to a host higher-dimensional gravity theory. We show that these theories can admit global symmetries, even anomalous ones; they can violate the cobordism, completeness, weak gravity, and distance conjectures; they may admit stable non-supersymmetric AdS vacua, or dS vacua. All swampland constraints are however satisfied when these gravity theories are regarded as relative and completed by coupling them to a higher-dimensional one.
We discuss these properties in d-dimensional gravity theories localized on Karch-Randall End of the World (ETW) boundaries of AdS_{d+1} spacetime. For AdSd ETW branes we use the formalism of double holography to describe the appearance of the species scale and the emergence of gauge dynamics from the quantum backreaction of CFT_d modes. We also study microscopically the swampland constraints in localized gravity in explicit string theory models. Concretely, we exploit the 10d supergravity solutions describing AdS_4 ETW branes for AdS_5×S^5, holographically dual to semi-infinite D3-branes ending on NS5- and D5-brane configurations, realizing 4d N=4 SU(N) on half-space coupled to a 3d Gaiotto-Witten superconformal boundary CFT3.
A348