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

本项目旨在促进对近共振状态下原子多体相互作用性质的理解，并将研究控制和操纵其量子力学特性的各种方法。虽然对少原子系统的理论描述极具挑战性，需要开发高效的数值和计算技术，但它提供了广泛而丰富的机会来推进科学知识，并具有潜在的技术影响。该项目是由美国国家科学基金会（NSF）和美以两国科学基金会（BSF）进行的理论和实验合作。理论和实验的结合将使人们对少原子过程有更深入的了解，这可能会导致原子钟、量子信息科学和探索许多新的物质相的各种应用。此外，这项研究的教育影响在于培养研究生和本科生最先进的理论和计算研究技术，为他们提供宝贵的技能和知识。最近用7Li原子对Efimov物理进行的实验观察显示出与理论计算的差异，突出了对普适性概念及其与该特定系统的相关性的更全面理解的必要性。锂原子具有独特的性质，使它们与超冷量子气体中其他常用的原子种类区别开来，需要更详细和严格的分析。具体来说，7Li原子之间的相互作用受到电子交换相互作用的强烈影响，即使在与范德华长度相当的显著距离上也是如此。因此，与目前正在研究的任何其他原子种类相比，7Li中的电子交换相互作用对Efimov物理的影响更大。解决这个问题将有助于开发精确的理论模型，以实现对少体过程的连贯控制。这种控制有可能通过最小化少体损失来稳定强相互作用气体，同时也为操纵三体相互作用和创建奇异的动力学体系提供了途径。值得注意的是，在7Li干涉实验中使用的叠加态的研究具有特别的兴趣。这些实验证明了相干性比叶菲莫夫陈述本身的寿命长几倍，这表明存在当前理论尚未完全理解的新物理现象。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.