Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux

Abstract

The model of a ring threaded by the Aharonov-Bohm flux underlies our understanding of a coupling between gauge potentials and matter. The typical formulation of the model is based upon a single particle picture, and should be extended when interactions with other particles become relevant. Here, we illustrate such an extension for a particle in an Aharonov-Bohm ring subject to interactions with a weakly interacting Bose gas. We show that the ground state of the system can be described using the Bose-polaron concept—a particle dressed by interactions with a bosonic environment. We connect the energy spectrum to the effective mass of the polaron, and demonstrate how to change currents in the system by tuning boson-particle interactions. Our results suggest the Aharonov-Bohm ring as a platform for studying coherence and few- to many-body crossover of quasi-particles that arise from an impurity immersed in a medium.

Aharonov-Bohm ring is an intuitive single-particle model applied across many fields of physics, but at the cost of neglecting the many-body interactions between particles and with the environment. Motivated by recent cold-atom experiments on Bose polarons, the authors study a particle contained in Aharonov-Bohm ring and weakly interacting Bose gas.