Superstars and Giant Gravitons in M-theory

TL;DR

This work extends the concept of giant gravitons as microscopic constituents of BPS naked singularities (superstars) from type IIB to M-theory, showing that AdS7×S4 and AdS4×S7 superstars can be viewed as sourced by continuous distributions of M2- and M5-branes expanding on the internal spheres. Using flux integrals and probe analyses, the authors derive explicit brane-density profiles and demonstrate that the total energy and angular momentum of these brane ensembles reproduce the supergravity masses for the BPS configurations. Probe calculations confirm the expansion mechanism, yielding BPS minima at the singular loci with relations such as Pφ1 = N sin θ1 (AdS7×S4) and Pφ1 = N sin^4 θ1 (AdS4×S7). The results reinforce a consistent M-theory interpretation of these superstars and highlight the role of giant gravitons in higher-dimensional AdS backgrounds, while noting limitations and avenues for further study due to higher-derivative corrections near the singularities.

Abstract

Following hep-th/0109127, we show that a certain class of BPS naked singularities (superstars) found in compactifications of M-theory can be interpreted as being composed of giant gravitons. More specifically, we study superstars which are asymptotically AdS_7 x S^4 and AdS_4 x S^7 and show that these field configurations can be interpreted as being sourced by continuous distributions of spherical M2- and M5-branes, respectively, which carry internal momenta and have expanded on the spherical component of the space-time.