Single neutral atoms coupled to a quantum gas forms a paradigm of open quantum systems. In a theory-experiment collaboration, we study the coherence properties of individual quantum systems coupled to an atomic bath. Experimentally, we immerse single or few Cesium atoms into an ultracold bath of Rubidium atoms.

We are particularly interested in revealing bath properties from monitoring the decoherence dynamics of the individual impurities, connecting the bath’s spectral function to experimentally obtained decoherence dynamics. Moreover, we aim on controlling the interaction between system and bath and study resonant spin-exchange interactions between single localize impurities and an engineered environment.

In addition, we will be interested in revealing the modification of impurity dynamics as the bath is tuned into a regime where the Markov approximation breaks down. Finally, we will explore realizing novel nonequilibrium atom-bath states by time-dependent drive of the impurity-bath interaction strength.

The project will thus shed light on central aspects of open system control that will be valuable for the many-body systems studied in research area B.