Dynamics of a Mobile Ion in a Bose-Einstein Condensate

TL;DR

This paper investigates the non-equilibrium dynamics of a charged impurity in a Bose-Einstein condensate, revealing superfluid effects, effective mass, and oscillatory behavior due to quantum correlations and long-range interactions.

Contribution

It provides a detailed analysis of impurity motion in a quantum medium, highlighting the effects of strong interactions and superfluidity on impurity dynamics.

Findings

Nonzero stationary momentum due to superfluidity

Effective mass from impurity dressing with atoms

Oscillatory dynamics from momentum transfer and density waves

Abstract

Characterization of the dynamics of an impurity immersed in a quantum medium is vital for fundamental understanding of matter as well as applications in modern day quantum technologies. The case of strong and long-ranged interactions is of particular importance here, as it opens the possibility to leverage quantum correlations in controlling the system properties. Here, we consider a charged impurity moving in a bosonic gas and study its properties out of equilibrium. We extract the stationary momentum of the ion at long times, which is nonzero due to the superfluid nature of the medium, and the effective mass which stems from dressing the impurity with the host atoms. The nonlinear evolution leads not only to emission of density waves, but also momentum transfer back to the ion, resulting in the possibility of oscillatory dynamics.