科研论文

返回至主页
  • Large scale quantum key distribution: Challenges and solutions [Invited]

    • 摘要:

      © 2018 Optical Society of America. Quantum key distribution (QKD) together with one time pad encoding can provide information-theoretical security for communication. Currently, though QKD has been widely deployed in many metropolitan fiber networks, its implementation in a large scale remains experimentally challenging. This letter provides a brief review on the experimental efforts towards the goal of global QKD, including the security of practical QKD with imperfect devices, QKD metropolitan and backbone networks over optical fiber and satellite-based QKD over free space.

    • 作者:

      Zhang Qiang;Xu Feihu;Chen Yu-Ao;Peng Cheng-Zhi;Pan Jian-Wei

    • 刊名:

      Optics Express

    • 在线出版时间:

      2018

  • Magnetic-enhanced modulation transfer spectroscopy and laser locking for 87 Rb repump transition

    • 摘要:

      © 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. Locking of a laser frequency to an atomic or molecular resonance line is a key technique in applications of laser spectroscopy and atomic metrology. Modulation transfer spectroscopy (MTS) provides an accurate and stable laser locking method which has been widely used. Normally, the frequency of the MTS signal would drift due to Zeeman shift of the atomic levels and rigorous shielding of stray magnetic field around the vapor cell is required for the accuracy and stability of laser locking. Here on the contrary, by applying a transverse bias magnetic field, we report for the first time observation of a magnetic-enhanced MTS signal on the transition of 87 Rb D 2 -line F g = 1 → F e = 0 (close to the repump transition of F g = 1 → F e = 2), with signal to noise ratio larger than 100:1. The error signal is immune to the external magnetic fluctuation. Compared to the ordinary MTS scheme, it provides a robust and accurate laser locking approach with more stable long-term performance. This technique can be conveniently applied in areas of laser frequency stabilization, laser manipulation of atoms and precision measurement.

    • 作者:

      Long Jin-Bao;Yang Sheng-Jun;Chen Shuai;Pan Jian-Wei

    • 刊名:

      Optics Express

    • 在线出版时间:

      2018

  • Observation of magnetically tunable Feshbach resonances in ultracold 23 Na 40 K + 40 K collisions

    • 摘要:

      © 2019 American Association for the Advancement of Science. All Rights Reserved. Resonances in ultracold collisions involving heavy molecules are difficult to simulate theoretically and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between potassium-40 ( 40 K) atoms and sodium-23–potassium-40 ( 23 Na 40 K) molecules in the rovibrational ground state. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atom-molecule Feshbach resonances are identified by observing an enhancement of the loss. We have observed 11 resonances in the magnetic field range of 43 to 120 gauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with exceptional resolution and will help to improve understanding of ultracold collisions.

    • 作者:

      Yang Huan;Zhang De-Chao;Liu Lan;Liu Ya-Xiong;Nan Jue;Zhao Bo;Pan Jian-Wei

    • 刊名:

      Science

    • 在线出版时间:

      2019

  • Genuine 12-Qubit Entanglement on a Superconducting Quantum Processor

    • 摘要:

      © 2019 American Physical Society. We report the preparation and verification of a genuine 12-qubit entanglement in a superconducting processor. The processor that we designed and fabricated has qubits lying on a 1D chain with relaxation times ranging from 29.6 to 54.6 μs. The fidelity of the 12-qubit entanglement was measured to be above 0.5544±0.0025, exceeding the genuine multipartite entanglement threshold by 21 statistical standard deviations. After thermal cycling, the 12-qubit state fidelity was further improved to be above 0.707±0.008. Our entangling circuit to generate linear cluster states is depth invariant in the number of qubits and uses single- and double-qubit gates instead of collective interactions. Our results are a substantial step towards large-scale random circuit sampling and scalable measurement-based quantum computing.

    • 作者:

      Gong Ming;Chen Ming Cheng;Zheng Yarui;Wang Shiyu;Zha Chen;Deng Hui;Yan Zhiguang;Rong Hao;Wu Yulin;Li Shaowei;Chen Fusheng;Zhao Youwei

    • 刊名:

      Physical Review Letters

    • 在线出版时间:

      2019

  • Experimental Gaussian Boson sampling

    • 摘要:

      © 2019 Science China Press Gaussian Boson sampling (GBS) provides a highly efficient approach to make use of squeezed states from parametric down-conversion to solve a classically hard-to-solve sampling problem. The GBS protocol not only significantly enhances the photon generation probability, compared to standard Boson sampling with single photon Fock states, but also links to potential applications such as dense subgraph problems and molecular vibronic spectra. Here, we report the first experimental demonstration of GBS using squeezed-state sources with simultaneously high photon indistinguishability and collection efficiency. We implement and validate 3-, 4- and 5-photon GBS with high sampling rates of 832, 163 and 23 kHz, respectively, which is more than 4.4, 12.0, and 29.5 times faster than the previous experiments. Further, we observe a quantum speed-up on a NP-hard optimization problem when comparing with simulated thermal sampler and uniform sampler.

    • 作者:

      Zhong Han-Sen;Peng Li-Chao;Li Yuan;Hu Yi;Li Wei;Qin Jian;Wu Dian;Jiang Xiao;Li Li;Liu Nai-Le;Lu Chao-Yang;Pan Jian-Wei;Dowling Jonathan P.;Zhang Weijun;Li Hao;Zhang Lu;Wang Zhen;You Lixing

    • 刊名:

      Science Bulletin

    • 在线出版时间:

      2019

  • Experimental quantum "guess my Number" protocol using multiphoton entanglement

    • 摘要:

      We present an experimental demonstration of a modified version of the entanglement-assisted "Guess my Number" protocol for the reduction of communication complexity among three separated parties. The results of experimental measurements imply that the separated parties can compute a function of distributed inputs by exchanging less classical information than by using any classical strategy. And the results also demonstrate the advantages of entanglement-enhanced communication, which is very close to quantum communication. The advantages are based on the properties of Greenberger-Horne-Zeilinger states.

    • 作者:

      Jun Zhang;Xiao Hui Bao;Teng Yun Chen;Tao Yang;Adán Cabello;建伟 潘

    • 刊名:

      Physical Review A - Atomic, Molecular, and Optical Physics

    • 在线出版时间:

      2007-2-5

  • 1.064-μm-band up-conversion single-photon detector

    • 摘要:

      Based on the technique of periodically poled lithium niobate waveguide, upconversion single-photon detection at 1.064-μm is demonstrated. We have achieved a system photon detection efficiency of 32.5% with a very low noise count rate of 45 counts per second by pumping with a 1.55-μm-band single frequency laser using the long-wavelength pumping technique and exploiting volume Bragg grating as a narrow band filter. Replacing the volume Bragg grating with a combination of adequate dielectric filters, a detection efficiency of up to 38% with a noise count rate of 700 counts per second is achieved, making the overall system stable and practical. The up-conversion single-photon detector operating at 1.064 μm can be a promising robust counter and find usage in many fields.

    • 作者:

      Fei Ma;Ming Yang Zheng;Quan Yao;Xiu Ping Xie;Qiang Zhang;建伟 潘

    • 刊名:

      Optics Express

    • 在线出版时间:

      2017-6-26

  • Observation of magnetically tunable Feshbach resonances in ultracold 23 Na 40 K + 40 K collisions

    • 摘要:

      Resonances in ultracold collisions involving heavy molecules are difficult to simulate theoretically and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between potassium-40 ( 40 K) atoms and sodium-23–potassium-40 ( 23 Na 40 K) molecules in the rovibrational ground state. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atom-molecule Feshbach resonances are identified by observing an enhancement of the loss. We have observed 11 resonances in the magnetic field range of 43 to 120 gauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with exceptional resolution and will help to improve understanding of ultracold collisions.

    • 作者:

      Huan Yang;De Chao Zhang;Lan Liu;Ya Xiong Liu;Jue Nan;博 赵;建伟 潘

    • 刊名:

      Science

    • 在线出版时间:

      2019-1-18

  • Integrating quantum key distribution with classical communications in backbone fiber network

    • 摘要:

      Quantum key distribution (QKD) provides information-theoretic security based on the laws of quantum mechanics. The desire to reduce costs and increase robustness in real-world applications has motivated the study of coexistence between QKD and intense classical data tra c in a single fiber. Previous works on coexistence in metropolitan areas have used wavelength-division multiplexing, however, coexistence in backbone fiber networks remains a great experimental challenge, as Tbps data of up to 20 dBm optical power is transferred, and much more noise is generated for QKD. Here we present for the first time, to the best of our knowledge, the integration of QKD with a commercial backbone network of 3.6 Tbps classical data at 21 dBm launch power over 66 km fiber. With 20 GHz pass-band filtering and large e ective core area fibers, real-time secure key rates can reach 4.5 kbps and 5.1 kbps for co-propagation and counter-propagation at the maximum launch power, respectively. This demonstrates feasibility and represents an important step towards building a quantum network that coexists with the current backbone fiber infrastructure of classical communications.

    • 作者:

      Yingqiu Mao;Bi Xiao Wang;Chunxu Zhao;Guangquan Wang;Ruichun Wang;Honghai Wang;Fei Zhou;Jimin Nie;Qing Chen;Yong Zhao;Qiang Zhang;Jun Zhang;Teng Yun Chen;建伟 潘

    • 刊名:

      Optics Express

    • 在线出版时间:

      2018-3-5

  • Memory-built-in quantum teleportation with photonic and atomic qubits

    • 摘要:

      The combination of quantum teleportation and quantum memory of photonic qubits is essential for future implementations of large-scale quantum communication and measurement-based quantum computation. Both steps have been achieved separately in many proof-of-principle experiments, but the demonstration of memory-built-in teleportation of photonic qubits remains an experimental challenge. Here, we demonstrate teleportation between photonic (flying) and atomic (stationary) qubits. In our experiment, an unknown polarization state of a single photon is teleported over 7m onto a remote atomic qubit that also serves as a quantum memory. The teleported state can be stored and successfully read out for up to 8s. Besides being of fundamental interest, teleportation between photonic and atomic qubits with the direct inclusion of a readable quantum memory represents a step towards an efficient and scalable quantum network.

    • 作者:

      宇翱 陈;Shuai Chen;Zhen Sheng Yuan;博 赵;Chih Sung Chuu;Jörg Schmiedmayer;建伟 潘

    • 刊名:

      Nature Physics

    • 在线出版时间:

      2008-2-21

共31页 转到