NSF-BSF: Universality Puzzles and Coherent Control of Efimov Physics with 7Li Atoms

This project aims to advance the understanding of the nature of atomic multi-body interactions in the nearly resonant regime and will study various methods for control and manipulation of their quantum mechanical properties. While a theoretical description of few-atom systems is extremely challenging, requiring the development of highly efficient numerical and computational techniques, it provides a broad and rich range of opportunities to advance scientific knowledge and has potential technological impact. This project represents a theoretical and experimental collaboration via the US National Science Foundation (NSF) and the US-Israel Binational Science Foundation (BSF). The combined theory and experimental effort will enable a deeper understanding of few-atom processes which may lead to various applications in atomic clocks, quantum information science, and the exploration of numerous novel phases of matter. Additionally, the educational impact of this research lies in training graduate and undergraduate students in state-of-the-art theoretical and computational research techniques, providing them with valuable skills and knowledge. Recent experimental observations of Efimov physics with 7Li atoms have exhibited discrepancies compared to theoretical calculations, highlighting the need for a more comprehensive understanding of the concept of universality and its relevance to this particular system. 7Li atoms possess unique properties that distinguish them from other commonly used atomic species in ultracold quantum gases, demanding a more detailed and rigorous analysis. Specifically, the interaction between 7Li atoms is strongly influenced by electronic-exchange interactions, even at significant distances comparable to the van der Waals length. Consequently, electronic-exchange interactions can have a greater impact on Efimov physics in 7Li than in any other atomic species currently under investigation. Addressing this question will enable the development of accurate theoretical models for achieving coherent control over few-body processes. Such control has the potential to stabilize strongly interacting gases by minimizing few-body losses, while also providing avenues to manipulate three-body interactions and create exotic dynamical regimes. Notably, the investigation of superposition states utilized in 7Li interferometric experiments holds particular interest. These experiments have demonstrated coherence times longer than the lifetime of Efimov states themselves, suggesting the existence of novel physical phenomena that current theory has yet to fully comprehend. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.