Multi-monopoles and Magnetic Bags

TL;DR

This paper demonstrates that multi-monopoles form magnetic bags in the large n limit, enabling simplified calculations of their properties and revealing a rich moduli space of solutions, with implications for string theory and cosmology.

Contribution

It introduces the concept of magnetic bags for multi-monopoles in the large n limit and analyzes their properties, including spectrum, shape, and relation to BPS solutions.

Findings

Magnetic bags saturate the Bogomol'nyi bound.

Infinite shapes of bags exist, indicating a moduli space.

Connections to string theory and cosmological monopole production.

Abstract

By analogy with the multi-vortices, we show that also multi-monopoles become magnetic bags in the large n limit. This simplification allows us to compute the spectrum and the profile functions by requiring the minimization of the energy of the bag. We consider in detail the case of the magnetic bag in the limit of vanishing potential and we find that it saturates the Bogomol'nyi bound and there is an infinite set of different shapes of allowed bags. This is consistent with the existence of a moduli space of solutions for the BPS multi-monopoles. We discuss the string theory interpretation of our result and also the relation between the 't Hooft large n limit of certain supersymmetric gauge theories and the large n limit of multi-monopoles. We then consider multi-monopoles in the cosmological contest and provide a mechanism that could lead to their production.