Emergence of non-abelian magnetic monopoles in a quantum impurity

Recently it was shown that molecules rotating in superfluid helium can be described in terms of
the angulon quasiparticles [1]. Here we demonstrate that in the experimentally realized regime the
angulon can be seen as a charge particle interacting with a gauge field of a non-abelian
magnetic monopole [2]. 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. The angulon
instabilities correspond to orbital angular momentum transfer between the impurity and the bath,
at which very strong, ‘anomalous’ screening can take place in the presence of a neutral, weakly-
polarizable environment [3]. 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.

[1] M. Lemeshko, Phys. Rev. Lett. 118, 95301 (2017).
[2] E. Yakaboylu, A. Deuchert, and M. Lemeshko, Phys. Rev. Lett., in press, arXiv:1705.05162.
[3] E. Yakaboylu and M. Lemeshko, Phys. Rev. Lett. 118, 85302 (2017).