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External Field Control of Ultracold Atom-Molecule Mixtures: Magnetic Feshbach Resonances and Sympathetic Cooling of Polyatomic Molecules

超冷原子分子混合物的外场控制：费什巴赫磁共振和多原子分子的交感冷却

基本信息

批准号：
1912668
负责人：
Timur Tscherbul
金额：
$ 27万
依托单位：
Board of Regents, NSHE, obo University of Nevada, Reno
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2022-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1912668&HistoricalAwards=false
关键词：
External Field Control Ultracold Atom

项目摘要

Quantum control of ultracold atoms, molecules, and ions with external electromagnetic fields is central to a wide variety of research fields. One widely-used control tool utilizes the sensitivity of long-lived quasi-stable (resonant) states between atoms. In particular, magnetic fields can be used to control so-called Feshbach resonances (MFRs) between atoms, a property that has been instrumental to the experimental realization of strongly correlated many-body states of matter for novel quantum materials. The prospect of controlling interactions of ultracold molecules is even more exciting, since these interactions are predicted to give rise to the highly exotic states of matter responsible for high-temperature superconductivity and novel topological phases. However, the tools for controlling molecular interactions with external magnetic fields are much less developed than those for atomic interactions, severely limiting the possibilities for controlling molecular many-body phenomena. The PI proposes to expand these possibilities by exploring MFRs in atom-molecule collisions using rigorous first-principle calculations. The study will pave the way toward precise quantum control of intermolecular interactions with applications to quantum simulation of condensed-matter systems, and to deep sympathetic cooling of trapped molecular gases.At present, numerically exact coupled-channel (CC) methodology cannot be used to study magnetic Feshbach resonances in ultracold atom-molecule collisions. This is due to the extreme computational difficulties caused by enormous CC basis sets, which must include all low-energy vibrational, rotational, and hyperfine molecular states coupled by strongly anisotropic intermolecular interactions. Particularly challenging to describe are the numerous hyperfine states, which arise due to the coupling between the electron and nuclear spins in the molecule, and play an important role in ultracold collisions. The PI proposes to address this issue by using flexible CC basis sets, which feature a variable number of hyperfine basis functions for different molecular rotational states. The use of the flexible basis states could reduce the computational complexity of CC calculations by several orders of magnitude, making it computationally feasible to calculate the spectrum of magnetic Feshbach resonances in ultracold atom-molecule mixtures of current experimental interest (such as Rb-SrF).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.

利用外部电磁场对超冷原子、分子和离子进行量子控制是各种研究领域的核心。一种广泛使用的控制工具利用原子之间的长寿命准稳定（共振）状态的灵敏度。特别是，磁场可以用来控制原子之间所谓的Feshbach共振（MFRs），这一特性有助于实验实现新型量子材料的强相关多体物质态。控制超冷分子相互作用的前景更令人兴奋，因为这些相互作用被预测会产生负责高温超导性和新颖拓扑相的高度奇异的物质状态。然而，用于控制分子与外部磁场相互作用的工具远不如用于原子相互作用的工具发达，严重限制了控制分子多体现象的可能性。PI建议通过使用严格的第一性原理计算探索原子-分子碰撞中的MFR来扩展这些可能性。这项研究将为精确控制分子间相互作用铺平道路，并将其应用于凝聚态系统的量子模拟，以及被困分子气体的深度共振冷却。目前，数值精确耦合通道（CC）方法无法用于研究超冷原子-分子碰撞中的磁Feshbach共振。这是由于巨大的CC基组所造成的极端计算困难，它必须包括所有低能量的振动，旋转和超精细分子状态耦合的强各向异性的分子间相互作用。特别具有挑战性的描述是众多的超精细状态，这是由于分子中电子和核自旋之间的耦合而产生的，并且在超冷碰撞中发挥重要作用。PI建议通过使用灵活的CC基组来解决这个问题，该基组具有用于不同分子旋转状态的可变数量的超精细基函数。灵活基态的使用可以将CC计算的计算复杂度降低几个数量级，使得计算当前实验感兴趣的超冷原子-分子混合物中的磁Feshbach共振谱在计算上是可行的（如Rb-SrF）该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的评估被认为值得支持。影响审查标准。

项目成果

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Spin coherence and optical properties of alkali-metal atoms in solid parahydrogen

DOI：
10.1103/physreva.100.063419
发表时间：
2019-10
期刊：
Physical Review A
影响因子：
2.9
作者：
S. Upadhyay;Ugne Dargyte;V. D. Dergachev;R. Prater;S. Varganov;T. Tscherbul;D. Patterson;J. Weinstein
通讯作者：
S. Upadhyay;Ugne Dargyte;V. D. Dergachev;R. Prater;S. Varganov;T. Tscherbul;D. Patterson;J. Weinstein

Near-threshold scaling of resonant inelastic collisions at ultralow temperatures