【校级报告】Lu+ clock comparison at the 10-18 level

报告人：张志强   

单位：新加坡国立大学   

主持人：盛继腾研究员   

时间：2023年2月20日（周一）上午10：00       

地点：光学大楼B225会议室    

报告人简介：

张志强，新加坡国立大学博士后研究员，2014年西安交通大学本科，2019年新加坡国立大学博士。博士期间从事冷原子研究，研究方向基于腔量子电动力学和多体物理的量子模拟，首次在实验中观察到超震荡辐射的量子相变。博士后期间主要从事镥原子光钟的研究，目前实验室的镥原子光钟每百亿年误差不超过1秒。迄今，在PRL, nature comm, Optica等学术期刊发表论文10余篇。

报告内容简介：

Singly ionized lutetium (¹⁷⁶Lu⁺) is a unique clock candidate with a number of attractive features for clock applications^[1],[2].  It provides three independent clock transitions allowing consistency checks of error budgets through frequency comparisons within the one system. In each case the clock frequency as realized as the average of all available m=0 hyperfine states.  The averaging eliminates shifts associated with the electronic angular momentum J and the use of exclusively m=0 states provide a high degree of insensitivity to magnetic fields. In previous work we have demonstrated the feasibility of multi-ion clock operation^[3] and measured a number of key systematics related to clock performance².

Recently, Comparisons between two independent Lu⁺ systems have been carried out using correlation spectroscopy on the ¹S₀-³D₁ clock transition.  A first set of comparisons is used to measure the residual quadratic Zeeman coefficient (QZC) of the hyperfine averaged clock frequency giving a value of -4.89171(74) Hz/mT².  Together with previous work, this allows an assessment of 1x10^-18 for the systematic uncertainty in the frequency difference between the two systems. Subsequent comparisons at ~0.1mT demonstrate agreement of the two oscillators with a statistical uncertainty of 3.2x10^-18, consistent with the assessment of systematics for each system.  This is the first use of correlation spectroscopy for clock assessment at this level and the first high accuracy clock comparison with this atom.