Operational effects of the UNOT gate on classical and quantum correlations  

作　　者：Kuan Zhang Jiajun Ma Xiang Zhang Jayne Thompson Vlatko Vedral Kihwan Kim Mile Gu 

机构地区：[1]Center for Quantum Information,Institute for Interdisciplinary Informotion Sciences,Tsinghua University,Beijing 100084,China [2]Department of Atomic and Laser Physics.Clarendon Laboratory,University of Oxford,Oxford OX1 3PU,UK [3]Department of Physics,Renmin University of China,Beijing 100872,China [4]Centre for Quantum Technologies,National University of Singapore,Singapore 117543,Singapore [5]Department of Physics,Notional University of Singapore,Singapore 117551,Singapore [6]School of Mathematical and Physical Sciences,Nanyang Technological University,Singapore 637371,Singapore [7]Complexity Institute,Nanyang Technological University,Singapore 637335,Singapore

出　　处：《Science Bulletin》2018年第12期765-770,共6页科学通报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2016YFA0301901);the National Natural Science Foundation of China(11374178 and 11574002);the National Research Foundation of Singapore(NRF Award No.NRF-NRFF2016-02 and project NRF2017-NRFANR004 Van Qu Te);the Competitive Research Programme(CRP Award No.NRF-CRP14-2014-02);the Ministry of Education in Singapore Tier 1 RG190/17;the Oxford Martin School

摘　　要：The NOT gate that flips a classical bit is ubiquitous in classical information processing.However its quantum analogue,the universal NOT(UNOT) gate that flips a quantum spin in any alignment into its antipodal counterpart is strictly forbidden.Here we explore the connection between this discrepancy and how UNOT gates affect classical and quantum correlations.We show that while a UNOT gate always preserves classical correlations between two spins,it can non-locally increase or decrease their shared discord in ways that allow violation of the data processing inequality.We experimentally illustrate this using a multi-level trapped ^(171)Yb^+ ion that allows simulation of anti-unitary operations.The NOT gate that flips a classical bit is ubiquitous in classical information processing. However its quan- tum analogue, the universal NOT （UNOT） gate that flips a quantum spin in any alignment into its antipo- dal counterpart is strictly forbidden. Here we explore the connection between this discrepancy and how UNOT gates affect classical and quantum correlations. We show that while a UNOT gate always preserves classical correlations between two spins, it can non-locally increase or decrease their shared discord in ways that allow violation of the data processing inequality. We experimentally illustrate this using a multi-level trapped 171yb＋ ion that allows simulation of anti-unitary operations.

关 键 词：Quantum information Universal NOT gate Quantum correlations Quantum discord Data processing inequality Embedding quantum simulation Ion trap 

分 类 号：O413[理学—理论物理]