Precision measurements beyond standard quantum limit in atomic vapor

报告题目：Precision measurements beyond standard quantum limit in atomic vapor

报告人：肖艳红  教授

主持人：蒋燕义  研究员

时间：2019-06-12 10:30

地点：理科大楼A207

主办单位：精密光谱科学与技术国家重点实验室

报告人简介：

肖艳红教授，1998年本科毕业于清华大学电子工程系，2000年硕士毕业于清华大学电子工程系。 2004年博士毕业于美国哈佛大学工程与应用物理学院，从事激光冷却原子的研究。 2004至2009年在哈佛-史密斯天文物理中心从事博士后研究。 2009年至今在复旦大学任教。长期致力于大原子系综量子精密测量的基本物理和技术的研究，完成了一系列有意义的、系统性创新工作。2013年获得基金委优秀青年基金资助。已发表含Nature Physics, PRL等在内的SCI论文共20余篇，目前主要研究兴趣集中在原子自旋压缩态，光的量子态（如压缩态）及其在突破标准量子极限的测量中的应用，如飞特斯拉级别原子磁力计。

报告内容简介：

Measurements lay at the foundation of physical science, and their ultimate precision is normally set by the standard quantum limit (SQL). Entangled states such as spin squeezed states, squeezed light can be used to break such limit, but previous experiments have largely been proof-of-principle, i.e., the absolute precision of those measurements, although beyond SQL, is relatively low. We have recently achieved spin squeezing for more than 100 billion atoms in a macroscopic vapor cell, exceeding the best angular resolving power in any spin squeezed state so far by 1000 times, with the aid of adiabatic pulse control and motional averaging. In a similar setup, a femtotesla level atomic magnetometer operated at room temperature was demonstrated， using a new weak-measurement spectroscopy. These results show potential benefits of entangled states even in practical and high-precision systems. In parallel, we are developing novel quantum light sources such as squeezed light array, quantum correlated beam array, by employing coherent diffusion of polaritons in vapor cells.Such light sources will find applications in quantum information science as well as quantum metrology.