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Continuous Variable Quantum Teleportation in Beam-Wandering Modeled Atmosphere Channel

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Chinese Physics Letters 2017年第4期34卷 5-8页

作者： Sheng-Li Zhang Chen-Hui Jin Jian-Hong Shi Jian-Sheng guo Xu-Bo Zou guang-can guo Information Science and Technology Institute The PLA Information Engineering University Zhengzhou 450004 Key Laboratory of Quantum information University of Science and Technology of China Hefei 230026

We investigate the continuous variable quomtum teleportation in atmosphere channels. The beam-wandering mode/is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is deterministic by increasing the aperture size of the detecting device and one is probabilistic by entanglement distillation, are proposed to improve the teleportation fidelity in the presence of atmosphere noises.

关键词： Continuous Variable Quantum Teleportation in Beam-Wandering Modeled Atmosphere Channel

Device-independent characterization of entanglement based on bell nonlocality

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Fundamental Research 2021年第1期1卷 27-42页

作者： Geng Chen Wen-Hao Zhang Peng Yin Chuan-Feng Li guang-can guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefeiAnhui 230026China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefeiAnhui 230026China

Quantum entanglement,has been acknowledged as a precious resource due to its inherent nonclassical correla-tions between *** quantum correlations have the potential for many quantum processes,includ-ing canonical ones:quantum cryptography,quantum teleportation,and dense *** exploit the advantages of quantum entanglement,two essential premises are required,i.e.,to prepare high-quality entanglement and characterize quality level of prepared *** far,quantum entanglement can be produced in various quantum systems;however,it appears that this new resource is complex and difficult to *** standard methods to characterize multipartite entanglement,e.g.,entanglement witness,state tomography,or quantum state verification,require full knowledge of the Hilbert space dimension and precise calibration of measurement devices,which are usually difficult to acquire in *** most radical way to overcome these problems is to detect entanglement solely based on the Bell-like correlations of measurement outcomes collected in the exper-iment,namely,device-independent characterization of *** article reviews the recently developed device-independent methods to characterize entanglement,including self-testing and device-independent certi-fication of *** approaches can be widely applied in kinds of quantum information processing,especially for those with security demands.

关键词： Quantum entanglement Device-independent characterization Self-testing Quantum nonlocality

Optical demonstration of quantum fault-tolerant threshold

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Light(Science & Applications) 2022年第8期11卷 1834-1842页

作者： Kai Sun Ze-Yan Hao Yan Wang Jia-Kun Li Xiao-Ye Xu Jin-Shi Xu Yong-Jian Han Chuan-Feng Li guang-can guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei230026China Hefei National Laboratory University of Science and Technology of ChinaHefei230088China

A major challenge in practical quantum computation is the ineludible errors caused by the interaction of quantum systems with their environment. Fault-tolerant schemes, in which logical qubits are encoded by several physical qubits, enable to the output of a higher probability of correct logical qubits under the presence of errors. However, strict requirements to encode qubits and operators render the implementation of a full fault-tolerant computation challenging even for the achievable noisy intermediate-scale quantum technology. Especially the threshold for fault-tolerant computation still lacks experimental verification. Here, based on an all-optical setup, we experimentally demonstrate the existence of the threshold for the fault-tolerant protocol. Four physical qubits are represented as the spatial modes of two entangled photons, which are used to encode two logical qubits. The experimental results clearly show that when the error rate is below the threshold, the probability of correct output in the circuit, formed with fault-tolerant gates, is higher than that in the corresponding non-encoded circuit. In contrast, when the error rate is above the threshold, no advantage is observed in the fault-tolerant implementation. The developed high-accuracy optical system may provide a reliable platform to investigate error propagation in more complex circuits with fault-tolerant gates.

关键词： quantum error operators

Optical Mode Entanglement Generation from an Optomechanical Nanobeam

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Chinese Physics Letters 2024年第11期41卷 62-76页

作者： Qi-Zhi Cai Bo-Yu Fan Yun-Ru Fan guang-Wei Deng You Wang Hai-Zhi Song guang-can guo Qiang Zhou Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 611731China Center for Quantum Internet Tianfu Jiangxi LaboratoryChengdu 641419China Key Laboratory of Quantum Physics and Photonic Quantum Information(Ministry of Education) University of Electronic Science and Technology of ChinaChengdu 611731China Southwest Institute of Technical Physics Chengdu 610041China CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China Jiangxi Research Institute University of Electronic Science and Technology of ChinaChengdu 641419China

Nano-optomechanical systems,capable of supporting enhanced light-matter interactions,have wide applications in studying quantum entanglement and quantum information ***,preparing optical telecomband entanglement within a single optomechanical nanobeam remains *** propose and design a triply resonant optomechanical nanobeam to generate steady-state entangled propagating optical modes and present its quantum-enhanced performance for teleportation-based quantum state transfer under realistic ***,the entanglement quantified by logarithmic negativity can obtain E_(N)=***,with structural imperfections induced by realistic fabrication processes considered,the device still shows great *** with quantum interfaces between mechanical motion and solid-state qubit processors,the proposed device potentially paves the way for versatile nodes in long-distance quantum networks.

关键词： quantum beam preparing

Experimentally realizing efficient quantum control with reinforcement learning

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Science China(Physics,Mechanics & Astronomy) 2022年第5期65卷 13-20页

作者： Ming-Zhong Ai Yongcheng Ding Yue Ban JoséDMartín-Guerrero Jorge Casanova Jin-Ming Cui Yun-Feng Huang Xi Chen Chuan-Feng Li guang-can guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China International Center of Quantum Artifcial Intelligence for Science and Technology(Qu Artist)and Department of Physics Shanghai UniversityShanghai 200444China Department of Physical Chemistry University of the Basque Country UPV/EHUBilbao 48080Spai School of Materials Science and Engineering Shanghai UniversityShanghai 200444China IDAL Electronic Engineering DepartmentUniversity of ValenciaValencia 46100Spain IKERBASQUE Basque Foundation for ScienceBilbao 48009Spain

We experimentally investigate deep reinforcement learning(DRL)as an artificial intelligence approach to control a quantum *** verify that DRL explores fast and robust digital quantum controls with operation time analytically hinted by shortcuts to *** particular,the protocol’s robustness against both over-rotations and off-resonance errors can still be achieved simultaneously without any priori *** the thorough comparison,we choose the task as single-qubit flipping,in which various analytical methods are well-developed as the benchmark,ensuring their feasibility in the quantum system as ***,a gate operation is demonstrated on a trapped^(171) Yb^(+)ion,significantly outperforming analytical pulses in the gate time and energy cost with hybrid robustness,as well as the fidelity after repetitive operations under time-varying stochastic *** experiments reveal a framework of computer-inspired quantum control,which can be extended to other complicated tasks without loss of generality.

关键词： quantum control reinforcement learning trapped ion quantum computing noise robustness

Dipole–dipole interactions enhance non-Markovianity and protect information against dissipation

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Chinese Physics B 2019年第9期28卷 100-106页

作者： Xiao-Ye Xu Qin-Qin Wang Zhe Chen Yong-Jian Han Chuan-Feng Li guang-can guo Key Laboratory of Quantum Information of Chinese Academy of Sciences (CAS) University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

Preserving non-Markovianity and quantum entanglement from decoherence effect is of theoretical and practical significance in the quantum information processing *** this context, we study a system S that is initially correlated with an ancilla A, which interacts with the environment E via an amplitude damping *** also consider dipole-dipole interactions(DDIs) between the system and ancilla, which are responsible for strong *** investigate the impact of DDIs and detuning on the non-Markovianity and information exchange in different *** show that DDIs are not only better than detuning at protecting the information(without destroying the memory effect) but also induce memory by causing a transition from Markovian to non-Markovian *** contrast, although detuning also protects the information, it causes a transition from non-Markovian to the Markovian *** addition, we demonstrate that the non-Markovianity grows with increasing DDI strength and diminishes with increasing *** also show that the effects of negative detuning and DDIs can cancel out each other, causing a certain loss of coherence and information.

关键词： decoherence non-Markovianity dipole-dipole interactions entanglement

Harmonics-assisted optical phase amplifier

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Light(Science & Applications) 2022年第11期11卷 2748-2754页

作者： Wu-Zhen Li Chen Yang Zhi-Yuan Zhou Yan Li Yin-Hai Li Su-jian Niu Zheng Ge Li Chen guang-can guo Bao-Sen Shi CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefeiAnhui 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

The change in the relative phase between two light fields serves as a basic principle for the measurement of the physical quantity that guides this *** would therefore be highly advantageous if the relative phase could be amplified to enhance the measurement *** well-known method for phase amplification involves the use of the multi-photon number and path-entangled state known as the NOON state;however,a high-number NOON state is very diffcult to prepare and is highly sensitive to optical *** we propose and experimentally demonstrate in principle a phase amplifer scheme with the assistance of a harmonic generation *** relative phase difference between two polarization modes in a polarized interferometer is amplified coherently four times with cascaded second-harmonic generation *** demonstrate that these amplification processes can be recycled and therefore have the potential to realize much higher numbers of multiple amplification *** phase amplification method presented here shows considerable advantages over the method based on NOON states and willbe highly promising for use in precision optical measurements.

关键词： process phase harmonic

Taking tomographic measurements for photonic qubits 88 ns before they are created

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Chinese Physics B 2021年第4期30卷 55-60页

作者： Zhibo Hou Qi Yin Chao Zhang Han-Sen Zhong guo-Yong Xiang Chuan-Feng Li guang-can guo Geoff J.Pryde Anthony Laing Key Laboratory of Quantum Information University of Science and Technology of ChinaCASHefei 230026China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Centre for Quantum Computation and Communication Technology(CQC2T)and Centre for Quantum Dynamics Griffith UniversityBrisbane4111Australia Quantum Engineering and Technology Laboratories School of Physics and Department of Electrical and Electronic EngineeringUniversity of BristolUK

We experimentally demonstrate that tomographic measurements can be performed for states of qubits before they are prepared.A variant of the quantum teleportation protocol is used as a channel between two instants in time,allowing measurements for polarization states of photons to be implemented 88 ns before they are *** data taken at the early time and later unscrambled according to the results of the protocol’s Bell measurements,produces density matrices with an average fidelity of 0.90±0.01 against the ideal states of photons created at the later *** tomography of the time reverse quantum channel finds an average process fidelity of 0.84±*** our proof-of-principle implementation necessitates some post-selection,the general protocol is deterministic and requires no post-selection to sift desired states and reject a larger ensemble.

关键词： teleportation tomography time reverse

Quantum twisted double-slits experiments:confirming wavefunctions'physical reality

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Science Bulletin 2017年第17期62卷 1185-1192页

作者： Zhi-Yuan Zhou Zhi-Han Zhu Shi-Long Liu Yin-Hai Li Shuai Shi Dong-Sheng Ding Li-Xiang Chen Wei Gao guang-can guo Bao-Sen Shi Wang Da-Heng Collaborative Innovation Center for Science of Quantum Manipulation&Control Heilongjiang Province&Harbin University of Science and TechnologyHarbin 150080China CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China Department of Physics Harbin University of Science and TechnologyHarbin 150080China Department of Physics and Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices Xiamen UniversityXiamen 361005China

Are quantum states real? This most fundamental question in quantum mechanics has not yet been satisfactorily resolved, although its realistic interpretation seems to have been rejected by various delayedchoice experiments. Here, to address this long-standing issue, we present a quantum twisted double-slit experiment. By exploiting the subluminal feature of twisted photons, the real nature of a photon during its time in flight is revealed for the first time. We found that photons' arrival times were inconsistent with the states obtained in measurements but agreed with the states during propagation. Our results demonstrate that wavefunctions describe the realistic existence and evolution of quantum entities rather than a pure mathematical abstraction providing a probability list of measurement outcomes. This finding clarifies the long-held misunderstanding of the role of wavefunctions and their collapse in the evolution of quantum entities.

关键词： Orbital angular momentum Subluminal group velocity Double slitsWave functions Physical reality