quantum    storage and manipulation

Experimental research of quantum information based on atomic ensemble is divided into quantum storage and manipulation of quantum coding and quantum states.


1. quantum storage


   Quantum communication system careering information based on a single photon is associated with the size of the encoded spatial dimensions. In traditional, photon coding in a two-dimensional space, and thus the amount of information carried by a photon is a bit. If one can encode a photon in a high-dimensional space (such as orbital angular momentum space), the amount of information carried by a single photon will  be increased significantly (by up to a bit bits, where d is the space dimension.) Also, the use of high dimensional coding photon state can also improve the security of quantum key transmission and have critical applications in the study of some of the fundamental problems of quantum mechanics. Realization of quantum networks in quantum communication must be employing a quantum repeater, which constitutes the core of the quantum storage unit named a quantum repeater. Implement and  Release photons carried information stored in the quantum storage unit is the essential function. Thus encoding photon in high dimensional space can improve the quantum efficiency of communication.

Our team carries out quantum critical issues around the scientific goals of high capacity communications. Experimental study of high-dimensional quantum memory based on the orbital angular momentum of photons encoded single-photon state, high-dimensional single-photon state, two-dimensional and high-dimensional entangled state quantum memory, creating a new direction in the field of quantum memory. We have published a series of papers in Nat. Comm., PRL, PRA, and other top academic journals, the main results are Nat. Photon. Recommended as a bright spot, the MIT and many other sites of Technology Review positive reviews, and Science, Nature extensive sub Journal, PRL references.




MIT's TechnologyReview:


http://www.technologyreview.com/view/514921/first-quantum-memory-that-records-the-shape-of-a-single-photon-unveiled-in-china

Main paper:

1. Dong-Sheng Ding, Zhi-Yuan Zhou, Bao-Sen Shi & Guang-Can Guo. Single-photon-level quantum image memory based on cold atomic ensembles. Nat. Commun. 4. 2527(2013).

2. Dong-Sheng Ding, Wei Zhang, Zhi-Yuan Zhou, Shuai Shi, Xi-Shi Wang, Yun-Kun Jiang, Bao-Sen Shi, and Guang-Can Guo. Quantum Storage of Orbital Angular Momentum Entanglement in an atomic ensemble. Physical Review Letters. 114, 050502 (2015).  


2. Broadband memory


  Quantum entanglement is a quantum core to build the network, storage and quantum entanglement, which is the key to achieve a quantum network. Broadband, high-speed information transmission and processing are the actual needs of the communication system. High bandwidth storage photon entangled states are the construction required high-speed quantum network information processing capability and have important implications for quantum information technology into practical usage. In many quantum storage scheme, Raman compared to other protocols such as the EIT protocol schemes have many advantages, such as large bandwidth signals can be stored, the storage system inhomogeneously broadened width is not sensitive, and the stored single photon having a frequency tonality. If we can achieve polarization entangled photon Raman storage, undoubtedly it has a considerable significance for the future to build the high-speed fiber-based quantum network.


   The scientific objectives of our group around the high-speed quantum information processing carried out key issues.


Experimental Study of broadband quantum memory for the first time to achieve a broadband single-photon-photon polarization entangled, which is to build for the future high-speed quantum network and a linear optical quantum computing foundation. The results, published in Nature Photonics 9. 332-338 (2015).


Main paper:


1.Dong-Sheng Ding, Yun Kun Jiang, Wei Zhang, Zhi-Yuan Zhou, Bao-Sen Shi, Guang-Can Guo. Optical precursor with four-wave mixing and storage based on a cold atomic ensemble. Physical Review Letters. 114, 093601 (2015).

2.Dong-Sheng Ding, Wei Zhang, Zhi-Yuan Zhou, Shuai Shi, Bao-Sen Shi, Guang-Can Guo. Raman Quantum Memory of Photonic Polarized Entanglement. Nature Photonics 9. 332–338(2015)