实验研究DQC1算法中的量子失谐  

Experimental investigation of quantum discord in DQC1

作　　者：李廷伟 伍旸 金芳洲 荣星 Tingwei Li;Yang Wu;Fangzhou Jin;Xing Rong(CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences,University of Science and Technology of China,Hefei 230026,China;CAS Center for Excellence in Quantum Information and Quantum Physics,University of Science and Technology of China,Hefei 230026,China;Department of Fundamental Subjects,Wuchang Shouyi University,Wuhan 430064,China)

机构地区：[1]中国科学技术大学,中国科学院微观磁共振重点实验室和物理学院,安徽合肥230026 [2]中国科学技术大学,中国科学院量子信息与量子科技创新研究院,安徽合肥230026 [3]武昌首义学院基础科学部,湖北武汉430064

出　　处：《中国科学技术大学学报》2022年第4期8-14,I0002,共8页JUSTC

基　　金：supported by the funding provided by the Educational Commission of Hubei Province (B2020298);the Natural Science Foundation of Hubei Province (2021CFB212);the Youth Innovation Promotion Association of Chinese A cademy of Sciences。

摘　　要：量子失谐被认为是确定性单比特量子计算(DQC1)中指数加速的来源。在实际噪声环境下实现DQC1算法并研究其中量子失谐的作用具有重要意义。我们在电子自旋共振(ESR)体系上演示了DQC1算法,并且观察到了非零的量子失谐。此外,我们发现量子失谐的大小与初态的纯度α及量子Fisher信息的大小具有对应关系。实验结果为揭示量子失谐在DQC1中的作用提供了有力证据,并有助于进一步理解量子算法中指数加速的来源。Quantum discord has been proposed as a resource responsible for the exponential speedup in deterministic quantum computation with one pure qubit(DQC1). Investigation of the quantum discord generated in DQC1 is of significant importance from a fundamental perspective. However, in practical applications of DQC1, qubits generally interact with the environment. Thus, it is also important to investigate the discord when DQC1 is implemented in a noisy environment.We implement DQC1 on an electron spin resonance(ESR) architecture in such an environment and nonzero quantum discord is observed. Furthermore, we find that the values of discord correspond to the values of purity α and quantum Fisher information, which reflect the power of the algorithm. Our results provide further evidence for the role of discord as a resource in DQC1 and are beneficial for understanding the origin of the power of quantum algorithms.

关 键 词：量子失谐 电子自旋共振 DQC1算法 

分 类 号：O413.1[理学—理论物理]