Ultracold Triatomic Molecules

超冷三原子分子

• 批准号: 2109995
• 负责人: John Doyle
• 金额: $ 75.8万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2109995&HistoricalAwards=false
• 关键词: Ultracold; Triatomic; Molecules

Atoms and molecules are the microscopic building blocks of the world. Their behavior and interactions are governed by the theory of quantum mechanics, which describes at a fundamental level much of modern science and technology. However, advancing quantum science and technology in the second quantum revolution requires cooling to temperatures around one millionth of a degree above absolute zero. Over the past several decades, powerful laser cooling techniques have been developed to reach these “ultracold” temperatures with atoms; in turn, a number of discoveries were made that shed light on the intricacies of quantum physics in complicated systems and led to the creation of a useful quantum computer. These techniques have more recently been extended to diatomic molecules (containing two atoms), but larger molecules (“polyatomic”) have so far eluded full quantum control. Cooling polyatomic molecules will shed light on the quantum nature of chemical reactions and be a resource for yet even more powerful quantum simulation, which can lead to the development of new technological materials. In this project, Professor John Doyle and his research team of graduate and undergraduate students and postdoctoral researchers will use laser cooling to trap CaOH (calcium monohydroxide) molecules at ultracold temperatures and then study their collisions, which will shed light on the quantum physics underlying molecular interactions. The aim is to eventually build a quantum computer using single molecule arrays of CaOH molecules.The experimental starting point of this work will be to cool and trap CaOH molecules in a magneto-optical trap (MOT). This will require scattering tens of thousands of optical photons from the molecules to remove energy and momentum, which is enabled by a careful understanding of the vibrational structure of CaOH developed recently by Professor Doyle and his research group. Because polyatomic molecules like CaOH cannot scatter photons indefinitely, they will then be transferred into a conservative optical dipole trap (ODT) -- where they can be held for several seconds without being lost. There, they can also be sub-Doppler cooled to temperatures near 1μK. By loading approximately 104 molecules into the ODT, sufficient density should be obtained to study collisions between CaOH molecules. After populating the molecules in an excited vibrational state and applying modest DC electric fields of ~1 kV/cm, it is expected that inelastic collisions will be effectively shielded, enabling evaporative cooling of triatomic molecules to even lower temperatures. The researchers additionally propose to load CaOH molecules into optical tweezers, which present an alternative route to collisional studies and could also be used to implement novel quantum simulation and computation schemes.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.

原子和分子是构成世界的微观构件。它们的行为和相互作用受量子力学理论的支配，该理论在基本层面上描述了许多现代科学和技术。然而，在第二次量子革命中推进量子科学和技术需要冷却到绝对零度以上百万分之一度左右的温度。在过去的几十年里，强大的激光冷却技术已经被开发出来，以达到原子的超低温；反过来，又有了一些发现，揭示了复杂系统中复杂的量子物理，并导致了有用的量子计算机的创造。这些技术最近已经扩展到双原子分子(包含两个原子)，但更大的分子(多原子)到目前为止还没有完全的量子控制。冷却多原子分子将揭示化学反应的量子本质，并成为更强大的量子模拟的资源，这可能导致新技术材料的开发。在这个项目中，John Doyle教授和他的研究生、本科生和博士后研究团队将使用激光冷却在超低温下捕获CaOH(氢氧化钙)分子，然后研究它们的碰撞，这将揭示分子相互作用背后的量子物理。其目标是最终利用CaOH分子的单分子阵列来构建量子计算机。这项工作的实验起点将是在磁光陷阱(MOT)中冷却和捕获CaOH分子。这将需要从分子中散射数万个光学光子来移除能量和动量，这是通过仔细理解Doyle教授和他的研究小组最近开发的CaOH的振动结构而实现的。因为像CaOH这样的多原子分子不能无限地散射光子，所以它们将被转移到保守的光学偶极陷阱(ODT)中--在那里它们可以保持几秒钟而不会丢失。在那里，它们还可以被亚多普勒冷却到接近1μK的温度。通过将大约104个分子加载到ODT中，应该可以获得足够的密度来研究CaOH分子之间的碰撞。在激发振动态填充分子并施加~1千伏/厘米的适度直流电场后，预计非弹性碰撞将被有效屏蔽，使三原子分子能够蒸发冷却到更低的温度。研究人员还建议将CaOH分子加载到光钳中，这为碰撞研究提供了一种替代途径，也可以用于实施新的量子模拟和计算方案。这一奖项反映了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。

项目成果

Blackbody thermalization and vibrational lifetimes of trapped polyatomic molecules

• DOI: 10.1103/physreva.107.062802
• 发表时间: 2023-03
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: N. Vilas;Christian Hallas;L. Anderegg;Paige Robichaud;Chaoqun Zhang;Sam Dawley;Lan Cheng;J. Doyle

Magneto-optical trapping and sub-Doppler cooling of a polyatomic molecule

• DOI: 10.1038/s41586-022-04620-5
• 发表时间: 2022-06-02
• 期刊: NATURE
• 影响因子: 64.8
• 作者: Vilas, Nathaniel B.;Hallas, Christian;Doyle, John M.
• 通讯作者: Doyle, John M.