CAREER: New Classical and Quantum Algorithms for Quantum Dynamics of Molecular Collisions and Chemical Reactions at Ultralow Temperatures

尽管利用外部电磁场控制化学反应的可能性几十年来一直令科学家们着迷，但场控制化学反应的实验演示必须等待开发出在超低温下冷却和捕获分子气体的巧妙技术。研究超冷化学反应如何在外部电磁场存在的情况下发生是很重要的，因为(1)这样的研究可以使科学家能够控制化学反应的结果，以及(2)他们提供的基本知识可以用来改进和完善复杂分子系统中化学反应如何发生的理论模型，通过使新型分子和材料的设计能够用于催化、光伏以及能量存储和转换，潜在地为社会提供深远的好处。该项目旨在解决超冷反应动力学领域中的两个主要限制，涉及(1)缺乏严格的理论方法来解释外场和超精细相互作用对超低温化学反应活性的影响，以及(2)由于计算复杂性随着反应络合物的大小而指数增加而导致的维度灾难问题。为此，PI将开发一种计算效率高的量子反应散射方法，该方法将充分考虑外部电磁场和超精细相互作用的影响。该方法将用于阐明外加磁场控制NaLi分子与钠原子的超冷反应的机理。为了解决维度灾难问题，PI将开发一种变分量子散射算法，用于解决近期有噪声的中等尺度(NISQ)量子计算机上的分子量子散射问题。该教育计划包括开发一门新的基于巨蟒的量子理论课程，为物理背景有限的学生提供较低的入学门槛，并与量子计算行业建立合作伙伴关系。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

While the possibility of controlling chemical reactions with external electromagnetic fields has fascinated scientists for decades, the experimental demonstration of field-controlled chemical reactivity had to wait for the development of ingenious techniques for cooling and trapping molecular gases at ultralow temperatures. It is important to study how ultracold chemical reactions occur in the presence of external electromagnetic fields because (1) such studies could enable scientists to steer the outcome of chemical transformations, and (2) the fundamental knowledge they provide could be used to refine and perfect theoretical models of how chemical reactions occur in complex molecular systems, potentially providing far-reaching benefits to society by enabling the design of novel molecules and materials for catalysis, photovoltaics, and energy storage and conversion. This project aims to address two major limitations in the field of ultracold reaction dynamics concerning (1) the lack of a rigorous theoretical approach to account for the effects of external fields and hyperfine interactions on chemical reactivity at ultralow temperatures, and (2) the curse of dimensionality problem due to the exponential increase of computational complexity with the size of the reaction complex. To this end, the PI will develop a computationally efficient quantum reactive scattering methodology, which will fully incorporate the effects of external electromagnetic fields and hyperfine interactions. The methodology will be applied to elucidate the mechanisms for controlling the ultracold reaction of NaLi molecules with sodium atoms by an external magnetic field. To address the curse of dimensionality problem, the PI will develop a variational quantum scattering algorithm for solving molecular quantum scattering problems on near-term noisy intermediate-scale (NISQ) quantum computers. The education plan involves the development of a new Python-based quantum theory course with a low barrier for entry for students with a limited physics background, and the establishment of a partnership with the quantum computing industry.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.