Title: Decomposition of multipartite permutation invariant state and its application to entanglement witness

Speaker: 马雄峰

  清华大学交叉信息研究院副教授，博士生导师。2003年北京大学物理学院学士，2008年多伦多大学物理系博士。先后在滑铁卢大学量子计算中心，多伦多大学，利兹大学从事博士后和访问学者。2012年到清华任教，主要从事量子密码学，量子信息基础，量子计算方向的研究。

Abstract:

  Tremendous efforts have been devoted to increase the number of controllable qubits in several quantum computing systems. For these implementations, it is crucial to certify the fidelity of the prepared multipartite quantum state as a base for further information processing. In this talk, I shall present a systematic method using very few local observables to measure the fidelity between a symmetric state and an unknown prepared state. The key is to decompose fidelity projection measure (a N-partite observable) with permutation symmetry using only $(N+1)(N+2)/2$ local measurement settings. This method is particularly effective for the fidelity estimation and entanglement detection of permutation-invariant states, such as the W state and Dicke states.

2021-4-16, 9:30AM, 腾讯会议