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Exploring Ultracold Matter Along the Complexity Axis

沿着复杂性轴探索超冷物质

基本信息

批准号：
1806971
负责人：
John Bohn
金额：
$ 26.9万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1806971&HistoricalAwards=false
关键词：
Exploring Ultracold Matter Along Complexity

项目摘要

Placing ordinary matter in extraordinary circumstances can create fascinating new phenomena and applications in physics. For example, it was realized some time ago that certain gases could be reduced to temperatures just a tiny bit above absolute zero, but without condensing into liquid drops. This new discipline of "ultracold" gases has led to a wealth of new understanding of quantum mechanical behavior of collections of simple atoms. Now, a new set of experiments seeks to enrich this discipline by introducing atoms and molecules with internal complexity. Doing so will lead to unprecedented detail in understanding and controlling chemical reactions, with applications yet to be dreamed of. Amazingly, it will in certain cases also allow for a deeper understanding of the fundamental rules of the universe than even the largest particle accelerator can provide. To carry out such experiments, it is necessary to thoroughly understand the dynamics of a complex, ultracold gas. This work will explore the role of complexity in the gas, considering phenomena such as basic thermodynamics, in which the propagation of heat or of sound can be different in different directions, or may depend on (and thus reveal) chemical reactivity. It will also consider the possibility, conjectured but not yet demonstrated, that molecules in the gas can stick to each other for brief amounts of time. Properties of this self-adhesive gas must be thoroughly understood before ultracold gases can be harnessed for applications. To do so, the work will investigate in detail the role of quantum chaos in the two-body collision dynamics. Chaos has already been demonstrated, or at least suspected, in ultracold collisions of lanthanide dimer atoms as well as alkali dimer molecules. The first steps have been taken, but a complete analysis, including the statistical distributions of energy levels and resonance widths, as well as the influence of magnetic fields, must still be undertaken. This analysis will be carried out using models of various degrees of complexity, to reveal the essential physics of the phenomena. Moreover, while the differential scattering cross sections of dipolar atoms and molecules are known, their complete influence on the thermodynamics of the gas remains largely unexplored. Dynamics of an ultracold dipolar gas will be undertaken, using Monte Carlo calculations.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.

将普通物质置于特殊环境中可以创造出迷人的新现象和物理学应用。例如，不久前人们意识到，某些气体可以被降低到比绝对零度高一点点的温度，但不会冷凝成液滴。这种新的“超冷”气体学科导致了对简单原子集合的量子力学行为的大量新理解。现在，一组新的实验试图通过引入具有内部复杂性的原子和分子来丰富这一学科。这样做将在理解和控制化学反应方面带来前所未有的细节，其应用还有待实现。令人惊讶的是，在某些情况下，它还允许对宇宙基本规则的更深入理解，甚至比最大的粒子加速器所能提供的还要深入。为了进行这样的实验，有必要彻底了解复杂的超冷气体的动力学。这项工作将探讨复杂性在气体中的作用，考虑到基本热力学等现象，其中热或声音的传播在不同方向上可能不同，或者可能取决于（从而揭示）化学反应性。它还将考虑一种可能性，即气体中的分子可以在很短的时间内相互粘在一起，这种可能性已经被证实，但还没有被证明。在将超冷气体用于应用之前，必须彻底了解这种自粘性气体的特性。为了做到这一点，这项工作将详细研究量子混沌在两体碰撞动力学中的作用。混沌已经被证明，或至少怀疑，在超冷碰撞的镧系二聚体原子以及碱金属二聚体分子。已经采取了第一步，但还必须进行完整的分析，包括能级和共振宽度的统计分布，以及磁场的影响。这种分析将使用各种复杂程度的模型进行，以揭示现象的基本物理学。此外，虽然偶极原子和分子的微分散射截面是已知的，但它们对气体热力学的完整影响在很大程度上仍未被探索。该奖项反映了NSF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。