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Jiang YF, Wei K, Huang L, Xu K, Sun QC, Zhang YZ, Zhang W, Li H, You L, Wang Z, Lo HK, Xu F, Zhang Q, Pan JW. Remote Blind State Preparation with Weak Coherent Pulses in the Field. PHYSICAL REVIEW LETTERS 2019; 123:100503. [PMID: 31573287 DOI: 10.1103/physrevlett.123.100503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Indexed: 06/10/2023]
Abstract
Quantum computing has seen tremendous progress in past years. Due to implementation complexity and cost, the future path of quantum computation is strongly believed to delegate computational tasks to powerful quantum servers on the cloud. Universal blind quantum computing (UBQC) provides the protocol for the secure delegation of arbitrary quantum computations, and it has received significant attention. However, a great challenge in UBQC is how to transmit a quantum state over a long distance securely and reliably. Here, we solve this challenge by proposing a resource-efficient remote blind qubit preparation (RBQP) protocol, with weak coherent pulses for the client to produce, using a compact and low-cost laser. We experimentally verify a key step of RBQP-quantum nondemolition measurement-in the field test over 100 km of fiber. Our experiment uses a quantum teleportation setup in the telecom wavelength and generates 1000 secure qubits with an average fidelity of (86.9±1.5)%, which exceeds the quantum no-cloning fidelity of equatorial qubit states. The results prove the feasibility of UBQC over long distances, and thus serves as a key milestone towards secure cloud quantum computing.
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Affiliation(s)
- Yang-Fan Jiang
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Kejin Wei
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Liang Huang
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ke Xu
- Centre for Quantum Information and Quantum Control, Department of Electrical & Computer Engineering and Department of Physics, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Qi-Chao Sun
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yu-Zhe Zhang
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Weijun Zhang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Hao Li
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Lixing You
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Zhen Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Hoi-Kwong Lo
- Centre for Quantum Information and Quantum Control, Department of Electrical & Computer Engineering and Department of Physics, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Feihu Xu
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Qiang Zhang
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jian-Wei Pan
- Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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2
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Feng Y, Wang T, Li Y, Li J, Wu J, Wu B, Jiang L, Wang C. Steering Metallofullerene Electron Spin in Porous Metal–Organic Framework. J Am Chem Soc 2015; 137:15055-60. [DOI: 10.1021/jacs.5b10796] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Yongqiang Feng
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Taishan Wang
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yongjian Li
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Li
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jingyi Wu
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Bo Wu
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Li Jiang
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chunru Wang
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Molecular Nanostructure
and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Wang WB, Zu C, He L, Zhang WG, Duan LM. Memory-built-in quantum cloning in a hybrid solid-state spin register. Sci Rep 2015; 5:12203. [PMID: 26178617 PMCID: PMC4503958 DOI: 10.1038/srep12203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/17/2015] [Indexed: 11/09/2022] Open
Abstract
As a way to circumvent the quantum no-cloning theorem, approximate quantum cloning protocols have received wide attention with remarkable applications. Copying of quantum states to memory qubits provides an important strategy for eavesdropping in quantum cryptography. We report an experiment that realizes cloning of quantum states from an electron spin to a nuclear spin in a hybrid solid-state spin register with near-optimal fidelity. The nuclear spin provides an ideal memory qubit at room temperature, which stores the cloned quantum states for a millisecond under ambient conditions, exceeding the lifetime of the original quantum state carried by the electron spin by orders of magnitude. The realization of a cloning machine with built-in quantum memory provides a key step for application of quantum cloning in quantum information science.
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Affiliation(s)
- W-B Wang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, PR China
| | - C Zu
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, PR China
| | - L He
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, PR China
| | - W-G Zhang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, PR China
| | - L-M Duan
- 1] Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, PR China [2] Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
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4
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Xiao X, Yao Y, Zhou LM, Wang X. Distribution of quantum Fisher information in asymmetric cloning machines. Sci Rep 2014; 4:7361. [PMID: 25484234 PMCID: PMC4258659 DOI: 10.1038/srep07361] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/19/2014] [Indexed: 11/21/2022] Open
Abstract
An unknown quantum state cannot be copied and broadcast freely due to the no-cloning theorem. Approximate cloning schemes have been proposed to achieve the optimal cloning characterized by the maximal fidelity between the original and its copies. Here, from the perspective of quantum Fisher information (QFI), we investigate the distribution of QFI in asymmetric cloning machines which produce two nonidentical copies. As one might expect, improving the QFI of one copy results in decreasing the QFI of the other copy. It is perhaps also unsurprising that asymmetric phase-covariant cloning outperforms universal cloning in distributing QFI since a priori information of the input state has been utilized. However, interesting results appear when we compare the distributabilities of fidelity (which quantifies the full information of quantum states), and QFI (which only captures the information of relevant parameters) in asymmetric cloning machines. Unlike the results of fidelity, where the distributability of symmetric cloning is always optimal for any d-dimensional cloning, we find that any asymmetric cloning outperforms symmetric cloning on the distribution of QFI for d ≤ 18, whereas some but not all asymmetric cloning strategies could be worse than symmetric ones when d > 18.
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Affiliation(s)
- Xing Xiao
- 1] College of Physics and Electronic Information, Gannan Normal University, Ganzhou, Jiangxi 341000, China [2] Beijing Computational Science Research Center, Beijing 100084, China
| | - Yao Yao
- Beijing Computational Science Research Center, Beijing 100084, China
| | - Lei-Ming Zhou
- 1] Beijing Computational Science Research Center, Beijing 100084, China [2] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaoguang Wang
- 1] Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China [2] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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5
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Chang YC, Liu GQ, Liu DQ, Fan H, Pan XY. Room-temperature quantum cloning machine with full coherent phase control in nanodiamond. Sci Rep 2013; 3:1498. [PMID: 23511233 PMCID: PMC3603226 DOI: 10.1038/srep01498] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 03/05/2013] [Indexed: 11/16/2022] Open
Abstract
In contrast to the classical world, an unknown quantum state cannot be cloned ideally, as stated by the no-cloning theorem. However, it is expected that approximate or probabilistic quantum cloning will be necessary for different applications, and thus various quantum cloning machines have been designed. Phase quantum cloning is of particular interest because it can be used to attack the Bennett-Brassard 1984 (BB84) states used in quantum key distribution for secure communications. Here, we report the first room-temperature implementation of quantum phase cloning with a controllable phase in a solid-state system: the nitrogen-vacancy centre of a nanodiamond. The phase cloner works well for all qubits located on the equator of the Bloch sphere. The phase is controlled and can be measured with high accuracy, and the experimental results are consistent with theoretical expectations. This experiment provides a basis for phase-controllable quantum information devices.
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Affiliation(s)
- Yan-Chun Chang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Gang-Qin Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Dong-Qi Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Heng Fan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xin-Yu Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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6
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Jones JA. Quantum computing with NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 59:91-120. [PMID: 21742157 DOI: 10.1016/j.pnmrs.2010.11.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 11/02/2010] [Indexed: 05/31/2023]
Affiliation(s)
- Jonathan A Jones
- Centre for Quantum Computation, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
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7
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Chen H, Lu D, Chong B, Qin G, Zhou X, Peng X, Du J. Experimental demonstration of probabilistic quantum cloning. PHYSICAL REVIEW LETTERS 2011; 106:180404. [PMID: 21635072 DOI: 10.1103/physrevlett.106.180404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Indexed: 05/30/2023]
Abstract
The method of quantum cloning is divided into two main categories: approximate and probabilistic quantum cloning. The former method is used to approximate an unknown quantum state deterministically, and the latter can be used to faithfully copy the state probabilistically. Thus far, many approximate cloning machines have been experimentally demonstrated, but probabilistic cloning remains an experimental challenge, as it requires more complicated networks and a higher level of precision control. In this work, we design an efficient quantum network with a limited amount of resources and perform the first experimental demonstration of probabilistic quantum cloning in a NMR quantum computer. In our experiment, the optimal cloning efficiency proposed by Duan and Guo [Phys. Rev. Lett. 80, 4999 (1998)] is achieved.
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Affiliation(s)
- Hongwei Chen
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China
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8
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Cucchietti FM, Zhang JF, Lombardo FC, Villar PI, Laflamme R. Geometric phase with nonunitary evolution in the presence of a quantum critical bath. PHYSICAL REVIEW LETTERS 2010; 105:240406. [PMID: 21231515 DOI: 10.1103/physrevlett.105.240406] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Indexed: 05/30/2023]
Abstract
Geometric phases, arising from cyclic evolutions in a curved parameter space, appear in a wealth of physical settings. Recently, and largely motivated by the need of an experimentally realistic definition for quantum computing applications, the quantum geometric phase was generalized to open systems. The definition takes a kinematical approach, with an initial state that is evolved cyclically but coupled to an environment--leading to a correction of the geometric phase with respect to the uncoupled case. We obtain this correction by measuring the nonunitary evolution of the reduced density matrix of a spin one-half coupled to an environment. In particular we are interested in baths near a quantum phase transition, which are known to induce strong decoherence. The experiments are done with a NMR quantum simulator, where we emulate qualitatively the influence of a critical environment using a simple one-qubit model.
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Affiliation(s)
- F M Cucchietti
- ICFO-Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels, Spain
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