基于量子中继的城际量子通信

研究方向

单光子信号在光纤等信道中传输时随着距离的增加而指数衰减,当衰减至与探测器的噪声水平相当时就将无法开展安全量子通讯,其限制了当前最远的距离为400公里左右。量子中继方案的提出原理上解决了这一问题。其基本思想为将一个远距离的量子信道分为较短的若干子信道;在每个子信道进行量子纠缠分发,并结合量子存储确定性产生子信道两端间的量子纠缠态;之后利用量子纠缠交换技术连接每段子信道,并利用纠缠纯化技术提升纠缠品质,最终实现在整个远距离信道首尾两端高效地建立量子纠缠;利用此异地纠缠即可开展任意的量子通讯方案了,如量子密钥分发、量子态隐形传输、分布式量子计算等。因此,量子存储及量子中继技术成为了远距离量子通信及未来量子网络系统中核心技术之一。在众多的量子存储物理体系中,冷原子系综具有满足量子中继需求的诸多优点,如利用集体增强效应易于实现高效读出、并且因处于真空低温环境退相干较小等。我们主要在冷原子量子存储的实验方向开展研究,主要包括进一步提升存储时间、读出效率、纠缠产生概率、通讯波段接口等主要存储性能,以及针对单一实验系统进行存储性能综合并开展多节点多级次的量子中继及量子网络研究等。希望通过以上研究将解决量子中继规模拓展过程中的关键障碍,使量子中继逐渐由原理走向实用。

相关论文

  • Wang, X. -J., Jing, B., Sun, P. -F., Yang, C. -W., Yu, Y., Tamma, V., Bao, X. -H. & Pan, J. -W. Experimental Time-Resolved Interference with Multiple Photons of Different Colors. Physical Review Letters 121, 080501 (2018).
  • Yang, S. -J., Wang, X. -J., Bao, X. -H. & Pan, J. -W. An efficient quantum light–matter interface with sub-second lifetime. Nature Photonics 10, 381-384 (2016).
  • Rui, J., Jiang, Y., Lu, G. -P., Zhu, M. -J., Zhao, B., Bao, X. -H. & Pan, J. -W. Demonstration of interferometric atom-pattern engineering via Rabi oscillations. Physical Review A 93, 033837 (2016).
  • Jiang, Y., Rui, J., Bao, X. -H. & Pan, J. -W. Dynamical zeroing of spin-wave momentum to suppress motional dephasing in an atomic-ensemble quantum memory. Physical Review A 93, 063819 (2016).
  • Li, J., Zhou, M. -T., Jing, B., Wang, X. -J., Yang, S. -J., Jiang, X., M\olmer, K., Bao, X. -H. & Pan, J. -W. Hong-Ou-Mandel Interference between Two Deterministic Collective Excitations in an Atomic Ensemble. Physical Review Letters 117, 180501 (2016).
  • Yang, S. -J., Wang, X. -J., Li, J., Rui, J., Bao, X. -H. & Pan, J. -W. Highly Retrievable Spin-Wave–Photon Entanglement Source. Physical Review Letters 114, 210501 (2015).
  • Yang, S. -J., Bao, X. -H. & Pan, J. -W. Modulation of single-photon-level wave packets with two-component electromagnetically induced transparency. Physical Review A 91, 053805 (2015).
  • Rui, J., Jiang, Y., Yang, S. -J., Zhao, B., Bao, X. -H. & Pan, J. -W. Operating Spin Echo in the Quantum Regime for an Atomic-Ensemble Quantum Memory. Physical Review Letters 115, 133002 (2015).
  • Zhao, T. -M., Zhang, H., Yang, J., Sang, Z. -R., Jiang, X., Bao, X. -H. & Pan, J. -W. Entangling Different-Color Photons via Time-Resolved Measurement and Active Feed Forward. Physical Review Letters 112, 103602 (2014).
  • Xu, X. -F., Bao, X. -H. & Pan, J. -W. Demonstration of active feedforward one-way quantum computing with photon-matter hyperentanglement. Physical Review A 86, 050304 (2012).