# Emergence of non-abelian magnetic monopoles in a quantum impurity problem

## TL;DR

This paper reveals that angulons, quasiparticles describing molecules in superfluid helium, can be modeled as non-abelian magnetic monopoles in real space, showing a topological transition near angulon instabilities, opening new experimental avenues.

## Contribution

It demonstrates the emergence of non-abelian magnetic monopoles in the angulon problem within real coordinate space, a novel topological aspect not previously identified.

## Key findings

- Angulons can be modeled as non-abelian magnetic monopoles on a 2-sphere.
- A topological transition occurs near angulon instabilities, changing monopole properties.
- Real-space gauge fields emerge in the angulon problem, unlike other settings.

## Abstract

Recently it was shown that molecules rotating in superfluid helium can be described in terms of the angulon quasiparticles (Phys. Rev. Lett. 118, 095301 (2017)). Here we demonstrate that in the experimentally realized regime the angulon can be seen as a point charge on a 2-sphere interacting with a gauge field of a non-abelian magnetic monopole. Unlike in several other settings, the gauge fields of the angulon problem emerge in the real coordinate space, as opposed to the momentum space or some effective parameter space. Furthermore, we find a topological transition associated with making the monopole abelian, which takes place in the vicinity of the previously reported angulon instabilities. These results pave the way for studying topological phenomena in experiments on molecules trapped in superfluid helium nanodroplets, as well as on other realizations of orbital impurity problems.