Dynamics of single neutral impurity atoms immersed in an ultracold gas

TL;DR

This paper demonstrates the controlled doping of an ultracold rubidium gas with single cesium impurity atoms, revealing insights into impurity dynamics, thermalization, and three-body loss rates in a highly controlled quantum environment.

Contribution

It presents the first realization of an ultracold gas doped with a known number of impurity atoms interacting via s-wave collisions, enabling precise study of impurity dynamics and interactions.

Findings

Rapid thermalization of impurity atoms inside the gas

Determination of Rb-Rb-Cs three-body loss rate with high precision

Controlled inelastic interactions limited to a single three-body recombination channel

Abstract

We report on controlled doping of an ultracold Rb gas with single neutral Cs impurity atoms. Elastic two-body collisions lead to a rapid thermalization of the impurity inside the Rb gas, representing the first realization of an ultracold gas doped with a precisely known number of impurity atoms interacting via s-wave collisions. Inelastic interactions are restricted to a single three-body recombination channel in a highly controlled and pure setting, which allows to determine the Rb-Rb-Cs three-body loss rate with unprecedented precision. Our results pave the way for a coherently interacting hybrid system of individually controllable impurities in a quantum many-body system.