**报告时间：**2023年8月14日下午2:30

**报告地点**：实验室一楼会议室

**报告人：**杨晶(Nordita)

**报告题目：****Precision Limits in Many-body Quantum Sensing
**

**报告摘要： **

Many-body interactions can introduce entanglement between particles and hence are valuable resources for quantum information processing. In quantum metrology, the precision can be further boosted by adding many-body interactions. In the first part of the talk, I will discuss the optimal control theory for controlling many-body quantum systems with restricted operations, in the context of quantum sensing and quantum state preparation. For quantum sensing, we show that in a spin chain model the Heisenberg scaling can be still achieved even though the control operations are restricted, given an initial GHZ-like state can be prepared.

In the second part of the talk, I will first briefly discuss experimental preparation of the GHZ state for a large number of particles can be very challenging and time-consuming. Therefore, we consider many-body sensing with separable initial states. We find that using separable initial states cannot beat the shot noise limit in locally interacting systems, unless long-range non-local interactions are utilized. These findings identify two important ingredients in many-body sensing: initial entanglement and long-range interactions.

References:

[1] Phys. Rev. Lett. 128, 160505(2022)

[2] arXiv: 2308.03696

**报告人简介： **

Jing Yang received his Ph.D. in 2021 from the University of Rochester. Currently, he is a fellow of Wallenberg Initiative on Networks and Quantum Information program at Nordita, Sweden. Prior to joining Nordita, he was a postdoc in the group of Prof. Adolfo del Campo at the University of Luxembourg from 2021-2023. His recent research topics focus on quantum metrology, quantum controls, one-dimensional integrable models, and open quantum systems.

编辑时间：2023-08-10 17:49:48