Precision Measurements with Laser-Cooled Cadmium: Optical-Lattice Clock and Cold Collision Experiments

使用激光冷却镉进行精密测量：光学晶格时钟和冷碰撞实验

• 批准号: 2012117
• 负责人: Kurt Gibble
• 金额: $ 59.22万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012117&HistoricalAwards=false
• 关键词: Precision; Measurements; Laser; Cooled; Cadmium

General audience abstract:The project will develop experimental techniques for optical-frequency atomic clocks based on Cadmium, an attractive candidate for the next generation of primary atomic clocks and an anticipated redefinition of international atomic time. Atomic clocks realize the most accurate measurements of any type. The small tick-rate differences and the short time intervals that atomic clocks routinely measure have wide-ranging applications, including the Global Positioning System (GPS), secure financial transactions, and official U.S. and international time. Scientific applications of atomic clocks include tests of general relativity and fundamental physics, geodesy, long baseline interferometry, and metrology. Atomic clocks address questions such as whether fundamental constants, for example the ratio of the mass of an electron and the mass of a proton, change in time. Just after the big bang, were fundamental constants different than they are now? The attractiveness of Cadmium atoms for highly accurate clocks and other precision measurements stems from an insensitivity of a suitable excitation of the atoms to thermal radiation from room-temperature surroundings, a limitation for many atomic clocks. Additionally, a practical aspect is that the lasers needed to make a Cadmium clock are expected to be more reliable than for other clock species with small thermal sensitivities. Cadmium also has a long series of eight isotopes, which have significantly different atom-atom collisions at the low temperatures used in clocks, within a millionth of a degree of absolute zero. The Cadmium isotopes include multiple bosons and fermions, which have different behaviors at ultra-cold temperatures. At such temperatures, the quantum-mechanical nature of atomic gases becomes evident and the basic science of these gases is of broad interest in modern physics research. The project will also provide training of graduate students in many areas of modern technology, including lasers, non-linear optics, the generation of coherent ultraviolet light, radio-frequency and microwave techniques, ultra-high vacuum, and atomic clocks and frequency control.Technical audience abstract:Specific goals for this research program include studying the ultracold scattering properties of the cadmium isotopes and investigating the frequency shifts due to the optical lattice light in a variety of lattice configurations. The lattice light frequency shifts depend non-linearly on the intensity due to magnetic dipole and electric quadrupole transitions, and the small hyperpolarizability of cadmium from two-photon transitions. Different lattice configurations can reduce tunneling between lattice sites at low lattice intensities, leading to smaller Doppler and lattice light shifts. The different configurations allow the light shifts to be studied to subsequently improve the accuracy of clocks. Another important component of the project is collaborations with atomic clock groups around the world, for example, to evaluate the accuracies of primary atomic clocks that contribute to International Atomic Time (TAI).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.

普通受众摘要：该项目将开发基于镉的光频原子钟的实验技术，镉是下一代主要原子钟的有吸引力的候选者，并且预计将重新定义国际原子时间。原子钟意识到任何类型的最准确测量值。原子钟通常衡量的小滴答差异和短时间间隔具有广泛的应用程序，包括全球定位系统（GPS），安全的金融交易以及美国和国际官方时间。原子钟的科学应用包括一般相对论和基本物理学的测试，地球，长基线干涉法和计量学。原子钟解决了诸如基本常数（例如电子的质量和质子质量之比）是否在时间上变化。大爆炸之后，基本常数与现在不同吗？镉原子对高度准确的时钟和其他精度测量的吸引力源于对原子对室温周围环境的热辐射的不敏感性，这是许多原子钟的限制。此外，一个实际方面是，与其他具有较小热敏感性的时钟物种相比，要使镉时钟的激光器需要更可靠。镉还具有一系列的八个同位素，在时钟中使用的低温下，它们的原子原子碰撞明显不同，距离绝对零的一百万分之一。镉同位素包括多个玻色子和费米子，它们在超冷的温度下具有不同的行为。在这种温度下，原子气体的量子力学性质变得明显，这些气体的基础科学在现代物理学研究中引起了广泛的兴趣。该项目还将在许多现代技术领域的研究生中提供培训各种晶格配置中的晶格灯。晶格光频移动非线性取决于磁偶极子和电二极管跃迁引起的强度，以及来自两光子过渡的镉的小超极化性。不同的晶格配置可以减少低晶格强度下的晶格位点之间的隧道，从而导致较小的多普勒和晶格光移。不同的配置允许研究光移，以提高时钟的准确性。该项目的另一个重要组成部分是与世界各地的原子钟组的合作，以评估有助于国际原子时间的主要原子钟的准确性（TAI）。该奖项反映了NSF的法定任务，并被认为是通过该基金会的知识分子和更广泛的影响来评估的支持，并被认为是值得的。

项目成果

Isotope shifts in cadmium as a sensitive probe for physics beyond the standard model

• DOI: 10.1088/1367-2630/acacbb
• 发表时间: 2022-08
• 期刊: New Journal of Physics
• 影响因子: 3.3
• 作者: B. Ohayon;S. Hofsass;J. E. Padilla-Castillo;S. Wright;G. Meijer;S. Truppe;K. Gibble;B. Sahoo

A many-channel FPGA control system

一种多通道FPGA控制系统

• DOI: 10.1063/5.0157330
• 发表时间: 2023
• 期刊: Review of Scientific Instruments
• 影响因子: 1.6
• 作者: Schussheim, Daniel T.;Gibble, Kurt
• 通讯作者: Gibble, Kurt