This award supports investigations into how gases of neutral atoms doped with charges (termed "hybrid systems") exhibit novel behaviors under extreme conditions, such as ultracold temperatures or quantum degeneracy. The PI will address two connected topics: (1) studies of hybrid samples under extreme conditions and their control, and (2) theoretical guidance for experimental detection of the predictions derived from these studies. Besides the immediate impact of the project in Atomic, Molecular and Optical Physics, a deeper understanding of charges in samples under extreme conditions is likely to support innovations such as the development of new frequency standards (e.g., hybrid atomic clocks, which are essential for navigation), quantum information processing (a fast growing field likely to dramatically change computing and sensors), and ultracold chemistry (e.g., by providing the detailed study and manipulation of chemical reactions). In addition, this grant will promote teaching and training of these topics. The research program under this grant seeks to gain knowledge of samples doped with charges under extreme conditions (e.g., ultracold temperatures or quantum degeneracy). The PI will explore ultracold hybrid systems with complex interactions, including atom-ion scattering with hyperfine structure and isotope shifts, charge hopping and Rydberg excitations near or at quantum degeneracy, and Rydberg electron interactions with exotic objects like Efimov trimers. Throug