Generation of frequency multiplexed entangled single photons assisted by the entanglement

We present a scheme to generate the frequency multiplexed entangled (FME) single photons based on the entanglement between two species atomic mixture ensemble. The write and reads fields driven according to a certain timing sequence, the generation of FME single photons can be repeated until success is achieved. The source might have significant applications in wavelength division multiplexing quantum key distribution.Comment: 4 pages, 4 figures, submitted to PR

Historical Study of China's Cultural Revolution and Its Coverage by the New York times

This thesis has generally adopted the Chinese Pinyin System of Romanization for transcribing Chinese names and places. Original spellings of names of persons and places have changed into Pinyin, which has been adopted by The New York Times for many years. For example, Peking is Beijing, Mao Tsetung is Mao Zedong and Liu Shao-ch'i is Liu Shaoqi, Chou Enlai ia Zhou Enlai. The original spelling is found only in quotations. The names of persons in this thesis are spelled in the traditional Chinese way, that is, surname first, except in the case of Nien Cheng, who chose to put her surname last in her book Life and Death in Shanghai. A few names of persons bear a hyphen between a two-word name. Such names were left as they appear in the quotations. Last of all, pinyin represent sounds similar to English sounds with only a few exceptions, such as c in Pinyin equals to ts in English; q equals to ch; x equals to sh; z equals to dz and zh equals to j.Mass Communication

Quantum tunneling time of a Bose-Einstein condensate traversing through a laser-induced potential barrier

We theoretically study the effect of atomic nonlinearity on the tunneling time in the case of an atomic Bose-Einstein condensate (BEC) traversing the laser-induced potential barrier. The atomic nonlinearity is controlled to appear only in the region of the barrier by employing the Feshbach resonance technique to tune interatomic interaction in the tunneling process. Numerical simulation shows that the atomic nonlinear effect dramatically changes the tunneling behavior of the BEC matter wave packet, and results in the violation of Hartman effect and the occurrence of negative tunneling time.Comment: 4 pages, 5 figure

Storage and retrieval of continuous-variable polarization-entangled cluster states in atomic ensembles

We present a proposal for storing and retrieving a continuous-variable quadripartite polarization-entangled cluster state, using macroscopic atomic ensembles in a magnetic field. The Larmor precession of the atomic spins leads to a symmetry between the atomic canonical operators. In this scheme, each of the four spatially separated pulses passes twice through the respective ensemble in order to map the polarization-entangled cluster state onto the long-lived atomic ensembles. The stored state can then be retrieved by another four read-out pulses, each crossing the respective ensemble twice. By calculating the variances, we analyzed the fidelities of the storage and retrieval, and our scheme is feasible under realistic experimental conditions.Comment: 6 pages, 4 figure