# Bound States of Little Strings and Symmetric Orbifold CFTs

## TL;DR

This paper investigates BPS bound states of little strings, revealing their partition functions relate to symmetric orbifold sigma models of monopole moduli spaces, thus connecting string theory and conformal field theories.

## Contribution

It provides new evidence linking monopole string partition functions in little string theories to symmetric orbifold CFTs, offering insights into their structure and dualities.

## Key findings

- Partition function of monopole strings matches symmetric orbifold CFT predictions
- Evidence of a deep connection between little strings and symmetric orbifold sigma models
- Monopole moduli space structure elucidated through string theory analysis

## Abstract

We study BPS bound states of little strings in a limit where they realise monopole strings in five dimensional gauge theories. The latter have gauge group $U(M)^N$ and arise from compactification of $(1,0)$ little string theories of type $A_{M-1} \times A_{N-1}$. We find evidence that the partition function of a certain subclass of monopole strings of charge $(k,\ldots,k)$ ($k\geq 1$) is expressible as the partition function of a symmetric orbifold sigma model, whose target space is precisely the symmetric product of the moduli space of monopoles with charge $(1, \ldots, 1)$.