From Gravitons to Giants
Avinash Dhar, Gautam Mandal, Mikael Smedbäck
TL;DR
Addressing nonperturbative gravity in the half-BPS sector, the paper uses exact bosonization of N fermions into N bosonic oscillators to analyze graviton dynamics in AdS5×S5 via the boundary theory. It shows that three-point graviton correlators grow exponentially with N at high energies, signaling breakdown of a graviton-based description well before reaching the Planck or AdS scales. The authors identify giant gravitons (and their oscillator/Schur-polynomial realizations) as weakly coupled bulk degrees of freedom that restore a tractable description, with single-particle states matching the giant-graviton spectrum. A universal, non-interacting bosonic description with a finite cutoff emerges, while Schur states illuminate the antisymmetric sector and clarify the bulk-boundary correspondence.
Abstract
We discuss exact quantization of gravitational fluctuations in the half-BPS sector around AdS$_5 \times $S$^5$ background, using the dual super Yang-Mills theory. For this purpose we employ the recently developed techniques for exact bosonization of a finite number $N$ of fermions in terms of $N$ bosonic oscillators. An exact computation of the three-point correlation function of gravitons for finite $N$ shows that they become strongly coupled at sufficiently high energies, with an interaction that grows exponentially in $N$. We show that even at such high energies a description of the bulk physics in terms of weakly interacting particles can be constructed. The single particle states providing such a description are created by our bosonic oscillators or equivalently these are the multi-graviton states corresponding to the so-called Schur polynomials. Both represent single giant graviton states in the bulk. Multi-particle states corresponding to multi-giant gravitons are, however, different, since interactions among our bosons vanish identically, while the Schur polynomials are weakly interacting at high enough energies.
