Exact Stringy Microstates from Gauge Theories

TL;DR

This paper explores the organization of BPS microstates in string theory via dual gauge theories, proposing a holographic method to compute their indices and examining how these microstates form bound states, including black holes.

Contribution

It introduces a new prescription for constructing string/brane configuration indices holographically from gauge theory determinants, advancing understanding of microstates at finite N.

Findings

Sum over giant graviton configurations reproduces gauge theory index.

Microstates are well-defined at finite N despite tensionless limit.

Bound states of branes can produce black hole degeneracies.

Abstract

We study how the microstates of BPS sectors in string theory are organized in the dual $U(N)$ gauge theory. The microstates take the form of a coherent sum of stacks of branes and their open/closed string excitations. We propose a prescription to holographically construct the indices of string/brane configurations by analyzing the modifications of determinant operators in gauge theory. The string/brane configurations should be interpreted in the tensionless limit, but their indices are well-defined at finite $N$. In various examples, we provide evidence that a sum, of the giant graviton-type recently proposed in the literature, over all such configurations gives the finite $N$ gauge theory index. Finally, we discuss how these microstates assemble in the BPS Hilbert space and in what circumstances the branes can form bound states to produce black hole degeneracies.