Efficient Scheme for the Generation of Atomic Schrödinger Cat States in an Optical Cavity

An efficient scheme is proposed for the generation of atomic Schroedinger cat states in an optical cavity. In the scheme N three-level atoms are loaded in the optical cavity. Raman coupling of two ground states is achieved via a laser tield and the cavity mode. The cavity mode is always in the vacuum state and the atoms have no probability of being populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and spontaneous emission.     

Measurement of the Wigner Characteristic Function for the Center－of－Mass Motion of Two Trapped Ions

We proposed a scheme for the reconstruction of the quantum states for the center-of-mass vibrational mode of two trapped ions. In the scheme the ions are multichromatically excited by three lasers. Then measurement of the difference between probabilities of the ions being both in electronic ground and excited states directly yields the Wigner characteristic function for the center-of-mass vibrational state. The scheme can also be used to prepare entangled coherent states for the center-of-mass and relative vibrational modes.     

Effects of periodic modulation on the nonlinear Landau--Zener tunneling

We study the Landau-Zener tunneling of a nonlinear two-level system by applying a periodic modulation on its energy bias. We find that the two levels are splitting at the zero points of the zero order Bessel function for high-frequency modulation. Moreover, we obtain the effective coupling constant between two levels at the zero points of the zero order Bessel function by calculating the final tunneling probability at these points. It seems that the effective coupling constant can be regarded as the approximation of the higher order Bessel function at these points. For the low-frequency modulation, we find that the final tunneling probability is a function of the interaction strength. For the weak inter-level coupling case, we find that the final tunneling probability is more disordered as the interaction strength becomes larger.     

关于五元环内酯开环反应性的商榷*

由于五元环特殊的热力学稳定性,高分子化学和有机化学教材中一般认为五元环内酯如γ-丁内酯(γ-BL)非常稳定,是不能开环聚合的单体。2016年,Hong和Chen从理论和实验2个方面证明了五元环γ-BL可以开环聚合。自此以后,有关γ-BL 及其衍生物的开环聚合被大量报道。本文系统论述了γ-BL及其衍生物的开环聚合,这有助于学生深入和正确认识五元环内酯的反应性。     

叶片弯曲变形对其结构稳定性的影响分析

本文针对柔性叶片能量转换装置的结构特点,在对四种弯曲变形叶片翼型气动载荷实验研究的基础上,采用参数化建模技术建立四种弯曲变形叶片实体模型,将实验测得的叶片表面压力加载到结构计算的有限元模型上,并以此为载荷对叶片进行气弹稳定性分析,揭示翼型发生变化后,叶片应力变化规律。研究结果表明:在一定的弯曲变形范围内,较大曲率弯曲变形的叶片结构稳定性较好。     

利用双模腔场与V型三能级原子共振作用隐形传送未知原子态

给出了双模腔场与V型三能级原子共振相互作用下系统态矢的演化公式.利用V型三能级原子与双模腔场的相互作用,通过控制原子与光场的相互作用时间,并对待传送的原子态进行选择性探测,从而实现未知双原子纠缠态的隐形传送.该方案不需要进行Bell基测量,其成功几率为1/16.     

Synthesis,Crystal Structure and Characterization of a New Zinc Citrate Complex

A new Zn-citrate coordination complex {K[Zn(C6H5O7)(H2O)]}n(1) was synthesized via hydrothermal reaction. In the crystal structure of complex 1, each citrate serves as the quadricdentate ligand coordinating to three Zn(II) ions, forming a zigzag chain, and such chains are further connected into a 3D network by the K+ linkers. Crystal data for complex 1: triclinic, space group P1, a = 7.3487(9), b = 7.5397(6), c = 9.6772(8) ?, α = 76.894(8), β = 68.260(10), γ = 65.155(10)°, V = 450.34(7) ?3 and Z = 2. Other characterizations by elemental analysis, IR, TG and fluorescence were also described.     

Electron-correlation-induced band renormalization and Mott transition in Ca1-xSrxVO3

We present the local density approximate+Gutzwiller results for the electronic structure of Ca_1-xSr_xVO₃. The substitution of Sr²⁺ by Ca²⁺ reduces the bandwidth, as the V—O—V bond angle decreases from 180° for SrVO₃ to about 160° for CaVO₃. However, we find that the bandwidth decrease induced by the V—O—V bond angle decrease is smaller as compared to that induced by electron correlation. In correlated electron systems, such as Ca_1-xSr_xVO₃, the correlation effect of 3d electrons plays a leading role in determining the bandwidth. The electron correlation effect and crystal field splitting collaboratively determine whether the compounds will be in a metal state or in a Mott-insulator phase.