Simplified Scheme for Cloning and Telecloning Quantum States near a Given State

We describe a simple protocol to produce two approximate copiers of an input state in the neighbourhood of a particular state.We show that the scheme can be realized within the framework of cavity quantum electrodynamics,We also present a scheme for telecloning this kind of states.     

量子微腔中腔场衰变对运动原子自发辐射的影响

通过分析环形微腔中单模量子电磁场与低速运动二能级原子相互作用过程中光子与原子质心的动量交换效应，本文详细研究了原子质心的运动多谱勒效应及光子反冲对原子能级自发辐射寿命的影响，本文理论证明了这效应起因子腔壁引起腔模的衰变，在一定条件下，原子质心运动将增强或低原子的自发辐射。     

《北京大学物理学丛书》书目

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Theoretical Study of Interesting Fine-Structure Splittings Based on a Scenario for Precise Calculations

Based on the multi-configuration Dirac-Fock self-consistent field method, a scenario has been presented to calculate the fine-structure energy levels of C^2＋ and Si^2＋ excited states （31 D2 and 33D1,2,3）. The Breit interactions and quantum electrodynamics corrections are added as perturbations. The present calculation results are found to be in excellent agreement with the experimental data. By means of the precise calculation procedure, we elucidate that four competitive mechanisms influence the interesting fine-structure splittings in C^2＋ and Si^2＋, such as spin-orbit interactions, relativistic corrections of exchange interactions, the Breit interactions and electron correlation effects. Furthermore, the mechanism of relativistic correction of exchange interactions has been studied clearly. We elucidate that the inner shell 2p1/2,3/2 orbitals are essential to relativistic corrections of exchange interactions which are crucial for the final anomalous fine-structure splittings.     

Scheme for implementing quantum dense coding with W-class state in cavity QED

An experimentally feasible protocol for realizing dense coding by using a class of W-state in cavity quantum electrodynamics （QED） is proposed in this paper. The prominent advantage of our scheme is that the successful probability of the dense coding with a W-class state can reach 1. In addition, the scheme can be implemented by the present cavity QED techniques.     

利用绝热过程制备GHZ态

提出一种利用绝热过程制备多原子GHZ态的方案.本方案可有效地抑制原子的自发辐射噪声.利用相似的方法可制备腔场GHZ态.制备成功的几率约为1.0.     

手征对称性动力学破缺和铜氧化物超导体相变的三维量子电动力学研究

利用三维量子电动力学理论中的Dyson-Schwinger方程方法, 研究了零温情况下平面铜氧化合物超导体的反铁磁相和d波超导相之间的相变. 通过在朗道规范下近似解析求解和数值求解完全耦合的Dyson-Schwinger方程、并将所得结果与1/N展开方法的结果相比较, 发现在半填充准费密子味道数约小于等于4的情况下, 通过手征对称性自发破缺, d波超导相可以演化到反铁磁相, 并且反铁磁相有可能与d波超导相共存. 通过进一步比较不同相的压强, 还说明反铁磁与d波超导共存相为稳定相, 从而反铁磁相确实可以与d波超导相共存.