Giant gravitons in AdS/CFT (I): matrix model and back reaction

TL;DR

This paper develops a matrix-model description of giant gravitons in AdS/CFT, recasting the BPS sector of N=4 SYM on R×S^3 in terms of matrix oscillators that reduce to a fermionic Fermi sea. Giant gravitons are mapped to Schur-polynomial operators acting on this sea, enabling the construction of quasi-classical (coherent) states that reproduce the classical AdS giant graviton solution, as well as a fully collective state with all D3-branes excited. By computing the CFT stress tensor and applying the AdS/CFT dictionary, the authors reconstruct the bulk backreaction and show it matches the supersymmetric Reissner–Nordström–AdS5 (STU) family of solutions, with charges tied to the CFT R-charges; the Liu–Sabra finite counterterm is necessary to cancel scheme-dependent Weyl anomalies. A key result is that GGs in AdS5 admit localized bulk descriptions in the quasi-classical regime, whereas GGs in S5 do not admit a bulk interior description, highlighting a qualitative difference between the two GG types. Overall, the work provides a concrete microscopic CFT construction for GG backreaction and opens routes to exploring near-BPS black holes and potential microstate counting within this matrix-model framework.

Abstract

In this article we study giant gravitons in the framework of AdS/CFT correspondence. First, we show how to describe these configurations in the CFT side using a matrix model. In this picture, giant gravitons are realized as single excitations high above a Fermi sea, or as deep holes into it. Then, we give a prescription to define quasi-classical states and we recover the known classical solution associated to the CFT dual of a giant graviton that grows in AdS. Second, we use the AdS/CFT dictionary to obtain the supergravity boundary stress tensor of a general state and to holographically reconstruct the bulk metric, obtaining the back reaction of space-time. We find that the space-time response to all the supersymmetric giant graviton states is of the same form, producing the singular BPS limit of the three charge Reissner-Nordström-AdS black holes. While computing the boundary stress tensor, we comment on the finite counterterm recently introduced by Liu and Sabra, and connect it to a scheme-dependent conformal anomaly.