SCIENCECHINA Physics, Mechanics & Astronomy  2014年第7期出版了Special Topic: Quantum Information（量子信息专题”），由龙桂鲁、潘建伟担任特邀编辑，专辑包含2篇综述，5篇研究论文及1篇研究快报，敬请关注：

http://phys.scichina.com:8083/sciGe/EN/volumn/volumn_6467.shtml      

Cover    Quantum information science promisessuperpowered capacities of computation, communication and metrology for thefuture. Quantum networks play a key role for realizing the physical implementationof quantum information science. In a quantum network, quantum information isgenerated, processed and stored locally at individual nodes which are linked byquantum channels. The carriers of quantum informationare quantum states. To transport quantum states from node to node in a networkwe have to distribute quantum entanglement across the entire network inadvance. For storing, processing and transmitting quantum information innetworks quantum states are converted from a physical system to another one ina reversible manner, which can be achieved by the interaction of light and atomsat nodes. The front cover painting is a schematic of quantum networks, in whichthe multi-partite entangled optical modes are generated by an entanglementsource and distributed to different nodes. The preparation of multi-partiteentangled states is an essential step for constructing a quantum network. Inthe paper we review the experimental progress in the generation ofmulti-partite and multi-color optical entangled states with continuous quantumvariables. These types of quantum entanglement provide the necessary resourcefor establishing continuous variable quantum information networks (See thereview by SU XiaoLong et al. on page 1210).

Editorial：

Quantumcommunication and quantum computation are two major branches of quantuminformation. In quantum communication, principles of quantum physics provide uswith the capability of on-site detection of eavesdropping (ODE). In quantum keydistribution, random numbers are distributed between two remote parties. If aneavesdropper is found, then the communicated data will be discarded. If no eavesdropperis found, the transmitted data is then post-processed to a very high securitylevel and used as keys. Quantum key distribution could not communicate secretmessage directly, because it cannot obliterate the information leakage beforeeavesdropper detection (OILBED). In quantum secure direct communication, notonly eavesdropper can be found on-site, but also the obliteration ofinformation leakage before eavesdropper detection can be realized. OILBED makesquantum secure direct communication to transmit secret messages directly. Ifthe communication is bi-directional, then it becomes a quantum dialogue. It isbelieved that a global quantum network could be built by running intra-cityquantum communication with fibers, and the inter-cityquantum communications by the use of ground-satellite, satellite-satellite, andsatellite-ground links. On the other hand, quantum principles enable quantumcomputer to compute or process much morepowerfully. The Shor algorithm, the Grover algorithm and simulations of quantumsystems are three major quantum algorithms. The simulation of quantumsystems is one of the important application of quantum computation in quantum computers with just a few quantum bits.In such prototype system, quantum algorithms can be demonstrated and studied.

This special topic of SCIENCE CHINA Physics, Mechanics &Astronomy collected eight papers. To be ready with satellite-ground quantumkey distribution, Wang et al. [1] completed an experimental validation work ondynamic polarization compensation. Su et al. [2] presented their work on thepreparation of entangled states for quantum network. Liang et al. [3] reviewedthe recent development on single-photon detection, a critical component inquantum communication and quantum computation. New protocols have also beenstudied. Zheng et al. [4] presented a protocol of quantum dialogue. Gao et al.[5] reported their minimum best success probability result in quantumtelegraphy. Quantum simulation of “zitterbewegung” using ion-trap scheme isproposed by Liu et al. [6]. An experimental realization of the quantum deletionalgorithm was given by Long et al. [7]. Finally, Zhao et al. [8] studied the longtime evolution of a spin in a spin bath, an important result that could help tofind a new candidate for quantum memory or quantum computation.

This special topic is onlypart of the efforts of the Chinese quantum information community at present. Wehope this special issue will reflect the on-going research effort of thequantum information community in China, and help to stimulate the efforts anddraw attention of respective researchers.

Prof. LONG GuiLu

Department of Physics, Tsinghua University

Prof. PAN JianWei

Department of Modern Physics, Universityof Science and Technology of China

专题篇目：

1  Wang C Z，Guo H，Ren J G，etal. Experimental validation of dynamic polarizationcompensation in ground-satellite quantum key distribution.Sci China-Phys Mech Astron, 2014, 57(7):1233–1237 PDF

2  Su X L, Jia X J, Xie C D, et al. Preparation of multipartite entangled states used forquantum information networks . Sci China-Phys Mech Astron, 2014,57(7): 1210–1217 PDF

3 Liang Y, Zeng H P. Single-photon detection and its applications.Sci China-Phys Mech Astron, 2014, 57(7): 1218–1232PDF

4  Zheng C, Long G F. Quantum secure direct dialogue usingEinstein-Podolsky-Rosen pairs. Sci China-Phys MechAstron, 2014, 57(7): 1238–1243 PDF

5  Gao F, Fang W, Wen Q Y. Minimum best success probability by classical strategiesfor quantum pseudo-telepathy. Sci China-Phys MechAstron, 2014, 57(7): 1244–1249 PDF

6  Liu T, Feng M, Yang W L, et al. Quantum simulation of‘zitterbewegung’ in a single trappedion under conditions of parity-keeping and parity-breaking.Sci China-Phys Mech Astron, 2014, 57(7): 1250–1255 PDF

7  Long Y, Feng G R, Pearson J, et al. Experimental quantum deletion in an NMR quantuminformation processor. Sci China-Phys Mech Astron,2014, 57(7): 1256–1261  PDF

8  Zhao Y K, Zhao M S, Chen Z B. Long time evolution of a spin interacting with a spin bathin arbitrary magnetic field. Sci China-Phys Mech Astron,2014, 57(7): 1262–1265  PDF