Invasion of the Giant Gravitons from Anti-de Sitter Space

TL;DR

The paper investigates the stringy exclusion principle in AdS/CFT by showing that massless bulk excitations on the sphere factor $S^m$ blow up into spherical branes as their angular momentum grows, thereby bounding the KK spectrum at $L_{ ext{max}}=N$ when the brane reaches the sphere radius $R$. Through detailed analyses in $AdS_7 imes S^4$, $AdS_5 imes S^5$, and $AdS_4 imes S^7$, the authors demonstrate that gravitons expand into M2, D3, or M5 branes respectively, with the brane size increasing with $L$ and the energy matching the BPS bound $E=L/R$ in the large-$N$ limit. This brane-blow-up mechanism provides a large-distance, noncommutative-like origin for the exclusion principle and ties holographic CFT operator bounds to bulk geometric constraints. The work thus strengthens the view of nonlocal gravity effects in AdS/CFT and offers a concrete brane-based picture for KK state truncation.

Abstract

It has been known for some time that the AdS/CFT correspondence predicts a limit on the number of single particle states propagating on the compact spherical component of the AdS-times-sphere geometry. The limit is called the stringy exclusion principle. The physical origin of this effect has been obscure but it is usually thought of as a feature of very small distance physics. In this paper we will show that the stringy exclusion principle is due to a surprising large distance phenomenon. The massless single particle states become progressively less and less point-like as their angular momentum increases. In fact they blow up into spherical branes of increasing size. The exclusion principle is simply understood as the condition that the particle should not be bigger than the sphere that contains it.