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

TL;DR

This paper explores giant gravitons within the AdS/CFT framework, using a matrix model to describe their CFT duals and holographically reconstructing the back-reacted bulk spacetime, revealing their relation to black hole solutions.

Contribution

It introduces a matrix model description of giant gravitons in CFT and provides a holographic method to compute their back reaction on spacetime geometry.

Findings

Matrix model captures giant graviton states as excitations or holes.

Holographic reconstruction yields back-reacted spacetime similar to BPS black holes.

Boundary stress tensor analysis links counterterms to conformal anomalies.

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-Nordstr\"om-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.