Towering Gravitons in AdS$_3$/CFT$_2$
Abstract
BPS states in holographic CFTs are usually classified into supergravitons, namely BPS fluctuations around empty AdS, and black-hole microstates, which appear above an energy threshold. In AdS/CFT, however, this picture is incomplete because of additional degrees of freedom, called singletons, associated with boundary diffeomorphisms. We present a general procedure for extending the BPS spectrum of supergravitons by dressing them with singletons, thereby defining a generalized, gravity-sector Hilbert space that admits decomposition into affine multiplets of the full superconformal algebra. This extends the procedure previously proposed in arXiv:2505.14888 which was applicable only at low levels, by removing that limitation. We apply the new procedure to the D1-D5 CFT and explicitly construct affine multiplets in the gravity sector for the theory up to level . We find that, at the free orbifold point, the gravity-sector spectrum agrees with the CFT up to . Upon turning on a deformation, however, states at lift and the agreement improves to . Interestingly, the lifting occurs between states in the gravity sector, involving mixtures of supergravitons and singletons, and stringy states. We conjecture that, upon deformation, the gravity-sector Hilbert space becomes the monotone Hilbert space while its complement becomes the fortuitous Hilbert space.
Cite
@article{arxiv.2604.20663,
title = {Towering Gravitons in AdS$_3$/CFT$_2$},
author = {Marcel R. R. Hughes and Kohei Jin and Daiki Matsumoto and Leon Miyahara and Masaki Shigemori},
journal= {arXiv preprint arXiv:2604.20663},
year = {2026}
}
Comments
27 pages plus appendices