Transportable optical clocks for key comparisons - 22IEM01 TOCK

近年来，光学钟取得了重大进展，明显超过了目前主要的时间和频率标准。目前建立的时间和频率关键比较使用基于卫星的技术，以10E-16分数不确定度提供国际一致性。欧洲几个NMI实验室之间有光纤连接，可以进行时钟比较，1E-18的不确定度很低，但这些受到相对论效应的限制。为了克服这些限制，并比较不能通过光纤链路互连的光钟，该项目将开发性能超过当前最先进水平的旅行频率标准。该项目将评估这些可移动光学时钟(TOC)作为频率标准的使用情况，并将论证它们在未来关键比较中使用的可行性。

In recent years, significant progress with optical clocks has been achieved, such that they clearly outperform current primary standards of time and frequency. The currently established key comparison for time and frequency uses satellite-based techniques to provide international consistency with 10E-16 fractional uncertainty. Optical fibre links between a few NMI laboratories in Europe are available and can enable clock comparisons with low 1E-18 uncertainty, but these are limited by relativistic effects. To overcome these limitations and to compare optical clocks that cannot be interconnected via optical fibre links, this project will develop travelling frequency standards with performance exceeding the current state-of-the-art. The use of these transportable optical clock (TOCs) as frequency standards will be evaluated by the project and their feasibility for use in future key comparisons will be demonstrated.