Optical lattice clocks for fundamental physics and redefinition of the second

用于基础物理和秒的重新定义的光学晶格钟

• 批准号: 2896457
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2896457
• 关键词: Optical; lattice; clocks; fundamental; physics

Atomic clocks are the most precise timekeeping devices. They work by stabilizing the frequency of some electromagnetic radiation so that it matches the frequency of an atomic energy level transition. Clocks based on Caesium 133 atoms provide the definition of the second in the international system of units and are used to realise Universal Coordinated Time and in technologies that require accurate timekeeping such as satellite navigation. Optical clocks work on the same principle as atomic clocks with the difference that they use radiation in the optical domain which has a higher frequency. The increased sensitivity that comes with this means that atoms need to be very carefully cooled down to uK temperatures, and optical lattice clocks also use optical light to trap atoms in a low kinetic energy state. These clocks are currently under development to become more reliable and robust but have already demonstrated higher precision than normal atomic clocks. This suggests that a new definition of the second will be needed so that the realisation of the second can be done using the more precise optical clocks. Another aspect of this increased precision that generates interest is the possibility of performing very accurate geodesy and investigating elusive phenomena such as variations in fundamental constants and dark matter. The objectives of this project are to contribute to the effort to redefine the second and to the fundamental Physics research by demonstrating clock operation with improved stability and by performing measurements of frequency ratios of clocks with different species (namely Strontium and Ytterbium ion) with enhanced precision.The novelty of the research stems from the new techniques employed to reduce the noise in the laser stabilization process. The limits of clock performance will be characterised by a mixture of theoretical considerations, newly developed computer simulations and experiments to investigate optimal operating parameters for an individual clock as well as composite architectures which combine two clocks to produce a more stable result than what is possible with a single clock. The solutions will propose changes in how the clock(s) is operated rather than changes to the experimental hardware.This work will be conducted at the National Physical Laboratory which is the metrology institute for the UK focusing on producing standards for measurement and calibration, and will also involve other metrology institutes in Europe, America and Asia through international measurement campaigns.

原子钟是最精确的计时装置。它们的工作原理是稳定某些电磁辐射的频率，使其与原子能级跃迁的频率相匹配。基于铯133原子的时钟提供了国际单位制中秒的定义，并用于实现世界协调时间和需要精确计时的技术，如卫星导航。光学钟的工作原理与原子钟相同，不同之处在于它们使用具有更高频率的光域中的辐射。随之而来的灵敏度增加意味着原子需要非常小心地冷却到uK温度，光学晶格钟也使用光学光将原子捕获在低动能状态。这些时钟目前正在开发中，以变得更加可靠和强大，但已经证明比普通原子钟更高的精度。这意味着需要一个新的秒的定义，以便使用更精确的光学时钟来实现秒。这种提高的精度的另一个方面是产生兴趣的是执行非常精确的大地测量和调查难以捉摸的现象，如基本常数和暗物质的变化的可能性。该项目的目标是通过演示具有改进稳定性的时钟操作以及通过以提高的精度测量具有不同种类（即锶和镱离子）的时钟的频率比来为重新定义秒的努力和基础物理学研究做出贡献。该研究的新奇源于用于减少激光稳定过程中的噪声的新技术。时钟性能的极限将通过理论考虑、新开发的计算机模拟和实验的混合来表征，以研究单个时钟以及复合架构的最佳操作参数，复合架构联合收割机将两个时钟结合起来，以产生比单个时钟更稳定的结果。解决方案将建议改变时钟的操作方式，而不是改变实验硬件。这项工作将在英国国家物理实验室进行，该实验室是英国的计量机构，专注于生产测量和校准标准，并将通过国际测量活动参与欧洲，美洲和亚洲的其他计量机构。