PM: Cold Radioactive Molecules for Precision Measurements.

PM：用于精密测量的冷放射性分子。

• 批准号: 2309361
• 负责人: Nicholas Hutzler
• 金额: $ 64.31万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309361&HistoricalAwards=false
• 关键词: PM; Cold; Radioactive; Molecules; Precision

The fact that the Universe is made from matter, yet contains no anti-matter, is a mystery. Nobody knows which physical process was responsible for generation of matter in the early Universe, but we do know that it can manifest itself in some unusual ways. One way is by modifying the electromagnetic properties of nuclei, which can be studied precisely in a table-top setting using laser-controlled and atoms and molecules. Some nuclei are more sensitive than others to these effects, and it has been known for decades that polar molecules containing certain heavy, unstable nuclei in the last row of the periodic table amplify the effects of this new physics by around a million times compared to current state-of-the-art experiments. However, these gains remain unrealized; the complexity of even the simplest molecule, combined with the limited amounts of unstable nuclei which can be obtained and handled in the laboratory, made this research very challenging. Indeed, the first precise laser-based measurement of any radioactive molecule was first performed a few years ago. For this present study, the PI will lead a team of students to develop and demonstrate a new method to synthesize, cool, and precisely study the structure and properties of molecules containing radium – one of the nuclei with the highest sensitivity to new fundamental physics. The research team will combine laser-driven chemical reactions, cryogenic helium gas cooling, and new approaches to precision spectroscopy to study polyatomic radium-containing molecules, whose chemical structures are tuned to enable advanced quantum control to study these exotic nuclei. Furthermore, the method will be widely applicable to molecules containing unstable or rare nuclei for studies in nuclear structure, radiochemistry, and nuclear astrophysics.Molecules containing heavy, octupole-deformed nuclei, such as radium, offer extreme enhancement of hadronic CP-violation. The combination of the intermolecular electromagnetic environment and the shape deformation of the nucleus result in around a million-fold enhancement in sensitivity to CP-violating nuclear Schiff moments compared to state-of-the-art experiments using atoms with spherical nuclei. Furthermore, many radium-containing molecules are predicted to be laser-coolable, meaning that they offer an avenue to advanced quantum control for highly sensitive measurements. However, the difficulty of working with these species has stifled their study; indeed, only in the last few years has precision spectroscopy been performed on any short-lived radioactive molecular species. The goal of this research program is to synthesize, cool, and spectroscopically study radium-containing polyatomic molecules, including RaOH, by combining laser-driven chemical synthesis, cryogenic buffer gas cooling, and new approaches to both broadband and narrowband spectroscopy with very small quantities of material. The method will produce molecules which are rotationally and translationally cooled to around 4 K in a static buffer gas cell, thereby placing them at a starting point for spectroscopy, laser cooling, and precision measurements. Furthermore, the methods will be very general, and can be applied to a wide variety of molecules containing exotic nuclei or otherwise available only in trace amounts.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.

宇宙是用物质制成的，但没有反物质，这是一个神秘的事实。没有人知道哪种物理过程是在早期宇宙中产生物质的原因，但是我们确实知道它可以以某种不寻常的方式表现出来。一种方法是修改核的电子特性，核的电子特性可以通过激光控制和原子和分子在桌面设置中进行精确研究。一些核对这些影响更敏感，几十年来，在元素周期表的最后一行中，极性分子含有某些重型，不稳定的核，与当前的最新实验相比，这种新物理学的影响增加了一百万倍。但是，这些收益仍未实现。即使是最简单的分子的复杂性，结合了可以在实验室中获得和处理的不稳定核的有限量，这使这项研究变得非常挑战。实际上，几年前首次对任何放射性分子进行了首个基于精确的激光测量。在本研究中，PI将导致一组学生开发并展示一种新方法，以合成，冷却和精确研究含有镭分子的结构和特性，这是对新基本物理的敏感性最高的核之一。研究小组将结合激光驱动的化学反应，低温氦气冷却以及用于研究含多原子半径的分子的新方法，其化学结构可以调节以实现高级量子控制以研究这些外来的核。此外，该方法将广泛适用于含有不稳定或稀有核的分子，用于核结构，放射化学和核天体物理学研究。含有重量，八杆的核（例如半径）的核分子可极大地增强耐药菌CP抗衡。与使用球形核核核的原子相比，分子间电磁环境和核的形状变形的组合在对CP竞争性核席夫的敏感性方面增强了约百万倍。此外，预计许多含有径向的分子是可以激光冷却的，这意味着它们为高度敏感的测量提供了高级量子控制的途径。但是，与这些物种一起工作的困难已经进行了研究。实际上，仅在过去几年中，对任何短寿命的放射性分子物种进行了精确光谱。该研究计划的目的是通过将激光驱动的化学合成，低温缓冲气体冷却以及宽带和窄带光谱与少量的材料的材料相结合，并通过将激光驱动的化学合成，低温缓冲液冷却和窄段光谱结合起来合成，冷却和光谱研究包括RaoH在内的含有径向的多原子分子。该方法将产生分子在静态缓冲液电池中旋转和翻译冷却至约4 K，从而将它们放置在光谱，激光冷却和精度测量的起点。此外，这些方法将非常笼统，可以应用于包含外来核的各种分子或仅在微量数量中获得的分子。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响标准来评估NSF的法定任务。