文献类型：期刊文献

英文题名：Direct estimation of quantum coherence by collective measurements

作者：Yuan, Yuan[1,2,3];Hou, Zhibo[1,3];Tang, Jun-Feng[1,3];Streltsov, Alexander[4];Xiang, Guo-Yong[1,3];Li, Chuan-Feng[1,3];Guo, Guang-Can[1,3]

机构：[1]Univ Sci & Technol China, CAS Key Lab Quantum Informat, Hefei 230026, Peoples R China;[2]East China Univ Sci & Technol, Dept Phys, Shanghai 200237, Peoples R China;[3]Univ Sci & Technol China, Synerget Innovat Ctr Quantum Informat & Quantum, Hefei 230026, Anhui, Peoples R China;[4]Univ Warsaw, Ctr Quantum Opt Technol, Ctr New Technol, Banacha 2c, PL-02097 Warsaw, Poland

年份：2020

卷号：6

期号：1

外文期刊名：NPJ QUANTUM INFORMATION

收录：;EI(收录号：20202208742799);WOS:【SCI-EXPANDED(收录号:WOS:000535362800001)】；

基金：We thank Huangjun Zhu for fruitful discussions. This work was supported by the National Natural Science Foundation of China (Grants No. 11574291 and No. 11774334), National Key Research and Development Program of China (Grants No. 2016YFA0301700 and No.2017YFA0304100), and Anhui Initiative in Quantum Information Technologies. A.S. acknowledges financial support by the "Quantum Coherence and Entanglement for Quantum Technology" project, carried out within the First Team programme of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund.

语种：英文

外文关键词：Quantum computers - Quantum optics - Computation theory - Quantum entanglement

摘要：The recently established resource theory of quantum coherence allows for a quantitative understanding of the superposition principle, with applications reaching from quantum computing to quantum biology. While different quantifiers of coherence have been proposed in the literature, their efficient estimation in today's experiments remains a challenge. Here, we introduce a collective measurement scheme for estimating the amount of coherence in quantum states, which requires entangled measurements on two copies of the state. As we show by numerical simulations, our scheme outperforms other estimation methods based on tomography or adaptive measurements, leading to a higher precision in a large parameter range for estimating established coherence quantifiers of qubit and qutrit states. We show that our method is accessible with today's technology by implementing it experimentally with photons, finding a good agreement between experiment and theory.