报告题目：Multi-ion clocks with In⁺ and Yb⁺ Coulomb crystals

报告人：Tanja Mehlstäubler 博士

报告人单位：德国Physikalisch-Technische Bundesanstalt (PTB)

主持人：蒋燕义研究员

地点：光学大楼B225会议室

时间：2024年4月16日（周二）下午14:00

报告内容：

In 2012, we proposed multi-ion spectroscopy to improve the stability of optical ion clocks which is fundamentally limited by the quantum projection noise of the single ion. Multi-ion clocks will not only improve the stability by exploiting the higher signal to noise of multiple ions or their uncertainty by allowing for sympathetic cooling of clock ions using a separate ion species but will be the basis for future entangled clocks and cascaded clocks. For the multi-ion approach we have developed and qualified scalable high-precision ion traps, which are already in use in several experiments. A challenge is the high level of control of systematic shifts when scaling up a single trapped ion to a complex many-body system. I will discuss our results in characterizing the shifts in multiple trapped ions and from lessons learned the potential of multi-ion spectroscopy. The multi-ion clock is operated in a recent dedicated experiment, where ¹¹⁵In⁺ ions are sympathetically cooled by ¹⁷²Yb⁺ ions. Here, I will report on the status of clock operation and international clock comparisons with fractional uncertainties at the level of low 10^-18. Last but not least, I will briefly discuss new world-record limits we obtained in our work on an improved test of local Lorentz invariance using ¹⁷²Yb⁺ ions and the search for new bosons using clock spectroscopy on even Yb⁺ isotopes.

报告人简介：

Tanja Mehlstäubler，2005年博士毕业于汉诺威大学，论文题目“Novel cooling methods for an optical frequency standard based on Mg atoms”。于2006年和2008年分别在巴黎天文台和德国PTB从事博士后研究，研究内容分别为冷原子重力仪和Yb⁺离子钟；2016年开始成为PTB/QUEST独立PI，目前为QUEST “Quantum Clocks and Complex Systems”部门负责人。主要研究方向包括量子传感、大地引力势测量、光钟与频标、精密测量等。