NSF-BSF: coherence and control of three-body interactions in ultracold quantum gases of 7LI atoms

The National Science Foundation Division of Physics awarded the University of Massachusetts Boston $282,335 on August 15, 2026, under the Mathematical and Physical Sciences program (CFDA 47.049) to conduct theoretical and experimental research on coherent control of three-body interactions in ultracold quantum gases of lithium-7 atoms as part of a US-Israel joint project.

The research combines advanced theoretical approaches with experimental techniques to deepen understanding of universality in few-body physics. The principal investigator will develop realistic theoretical models using hyper-spherical adiabatic representation to account for hyperfine and electrostatic interatomic interactions, and will extend Floquet formalism to implement coherent control over few-body collision processes. The experimental work will explore novel interaction regimes including Efimov phenomena in lithium-7 and physics near narrow Feshbach resonances. The studies of few-body superposition states will enable precision measurements of interactions and new methods for manipulating few-body collisions to enhance stability and lifetime of strongly interacting quantum systems. The project includes training of graduate and undergraduate students in theoretical and experimental quantum gas physics.

The award period extends through July 31, 2029, with performance taking place at the University of Massachusetts Boston campus in Dorchester, Massachusetts.

Abstract

This US-israel joint project will deepen our understanding of fundamental aspects of ultracold quantum gases and the development of coherent control of few-body collisions and interactions. The intellectual merit of this project lies in advancing the understanding of universality in few-body physics through the development of realistic theoretical models and the exploration of novel interaction regimes via coherent control. By combining these advanced theoretical approaches with innovative experimental techniques, the PI will provide the most comprehensive analysis of few-body physics in ultracold quantum gases, including a deeper understanding of a puzzling effect called efimov phenomena in 7LI and the exploration of physics near narrow feshbach resonances. These studies of few-body superposition states will have strong implications for precision measurements of the interactions, while the investigations of the coherent control of few-body collisions will enable new methods for manipulating these interactions and enhancing the stability and lifetime of strongly interacting quantum systems. The PI will use innovative approach, combining theory and experiment to train students in this important field of physics. The theoretical studies will be performed using the hyper-spherical adiabatic representation where hyperfine and electrostatic interatomic interactions are taken into account in order to accurately describe 7LI behavior. The implementation of coherent control over few-body processes will be performed by extending floquet formalism to account for the non-perturbative nature of the interatomic interactions. Additionally, the PI will explore regimes in which collective behavior is dominated by three-body interactions, either by suppressing two-body correlations or by enhancing three-body processes. Altogether, these studies promise to push the frontiers of collective phenomena in quantum physics in previously inaccessible dynamical regimes. 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.- subawards are not planned for this award.