On Grey Galaxies and D3-branes on the Conifold

Abstract: We study the effective potentials for various probe D-branes surrounding AdS$_5$ black holes in consistent truncations of type IIB supergravity on Sasaki-Einstein 5-manifolds $Y<sup>{p,q}$, focusing in particular on the conifold base $T<sup>{1,1}$. The probes are either dual Giant Gravitons having support on AdS spacetime dimensions or D3 probe branes wrapped on non-contractible cycles of the internal manifold, which then appear "point-like" in the AdS spacetime. The non-contractible cycles of $T<sup>{1,1}$ and $Y<sup>{p,q}$ topologically stabilize the branes at a finite size, and we find stable supersymmetric wrapped D3 branes on Gutowski-Reall black holes, effectively providing a stable BPS composite system in AdS$_5$ made by a black hole surrounded by a baryonic condensate. We show that the onset of superradiance in the black hole backgrounds matches the emergence of stable minima in the probe effective potentials, extending the constructions of Dual Dressed Black Holes and the Grey Galaxies. We comment on the relevance of this result for recent studies concerning the classical cohomology problem and the associated fortuitous states in the dual Klebanov-Witten theory.