M2-M5 giant graviton expansions

TL;DR

This paper derives exact closed-form expressions for indices related to M5-brane giant gravitons in M2-brane SCFTs, revealing new insights into the spectra of BPS states in 6d theories.

Contribution

It provides the first closed-form formulas for the indices of 1/4- and 1/3-BPS M5-brane giant gravitons, expanding understanding of these spectra in M-theory.

Findings

Exact forms of twisted indices for 6d (2,0) theories are obtained.

Indices for M5-brane giant gravitons are expanded in terms of M2-brane indices.

The results generalize unrefined indices and confirm their expansion structure.

Abstract

We examine the giant graviton expansions of the Coulomb and Higgs indices for the M2-brane SCFTs to find the closed-form expressions for the indices that encode the spectra of the $1/4$-BPS M5-brane giant gravitons and the $1/3$-BPS orbifold M5-brane giant gravitons. Consequently, we get exact forms of the twisted indices for the 6d $(2,0)$ theories describing a stack of $N$ M5-branes which generalize the unrefined indices. We confirm that they are also beautifully expanded with respect to the indices for the M2-brane giant gravitons which are obtained from the Coulomb and Higgs indices for the M2-brane SCFTs upon the change of variables.