具有三重Mo—Mo键的配合物Mo_2Cl_6[SC(NH_2)_2]_3·2H_2O合成、晶体结构和电子构型

分别通过Mo≡Mo→Mo≡Mo的双电子氧化还原反应及由单核Mo(Ⅲ)配合物经硫脲[SC(NH_2)_2]桥联的方法合成具有三重Mo—Mo键的配合物Mo_2Cl_5[SC(NH_2)_2]_3·2H_O.该配合物晶体的结晶学参数为:三斜晶系,PI空间群,.晶胞中2个结晶学独立的分子中Mo—Mo键长分别为2.439(1)A和2.443(1)A.配合物的S-C键削弱了桥S原子参与d-p相互作用的程度,有利于形成较强的Mo≡Mo键,其d-d分子轨道的电子构型是ν~2(π+δ)~4.     

THE FIRST BOUNDARY VALUE PROBLEM FOR STRONGLY DEGENERATE QUASILINEAR PARABOLIC EQUATIONS IN ANISOTROPIC SOBOLEV SPACES

This article concerns the existence of weak solutions of the first boundary value problem for a kind of strongly degenerate quasilinear parabolic equation in the anisotropic Sobolev Space. With the theory of anisotropic Sobolev spaces an existence result is proved.     

连续变量无条件纠缠交换 --纠缠态的量子离物传送

利用自行设计的两台非简并光学参量放大器，获得了一对具有经典相干性且量子起伏相互独立的连续变量纠缠态光场，并用它完成了连续变量的无条件纠缠交换，即纠缠态的量子离物传送．通过联合贝尔态探测与纠缠塌缩，使两个初始不纠缠而又从未发生过直接相互作用的光场产生了量子纠缠，其正交振幅和位相分量的量子起伏关联方差被直接测量，其测量值分别低于散离噪声极限1．23dB和1．12dB．理论计算与实验结果基本符合．     

用短程飞行时间谱对铯MOT温度的测量以及铯MOT中冷原子吸收光谱研究

介绍采用短程飞行时间(Time-of-flight:TOF)吸收谱测量铯磁光阱(MOT)中冷原子云温度的实验方案和结果.MOT中冷原子的温度是一个非常重要的参数.与通常的飞行时间荧光谱方法不同,我们采用短程飞行时间吸收谱来测量MOT温度.在MOT区域下方h处打一束柱状探测光束(实验中我们对于h = 2 mm～8 mm的情况作了对比研究),释放冷原子云后在其膨胀和自由下落过程中穿过探测光束即可测得TOF吸收谱,由此可推知MOT温度.在直径约15 mm的六束冷却与俘获光每束8 mW功率、相对于铯D2线Fg=4 - Fe=5冷却循环跃迁红失谐约10 MHz、四极磁场轴向梯度约11 Gauss/cm的条件下,由h = 3 mm时典型的短程TOF吸收谱推得相应的冷原子温度约70 μK,低于铯原子多普勒冷却极限TD=125 μK.此外,在冷却光及repumping光均开启的情况下,我们还对于MOT中冷却与俘获的铯原子的吸收光谱进行了研究,并使用Dress原子模型作了相应的分析.     

Fidelity of Quantum Teleportation for Single-Mode Squeezed State Light

The fidelity of quantum teleportation of a single-mode squeezed state of light is calculated based on the general theory of quantum-mechanical measurement in the Schrodinger picture. It is shown that the criterion for the nonclassical state teleportation is different from that for coherent state. F = 1/2 is no longer the rigorous boundary between classical and quantum teleportation for a squeezed state of light. When the quantum entanglement of an Einstein-Podolsky-Rosen （EPR） beam used for teleportation and the parameters of the system are given, the fidelity depends on the squeezing of the input squeezed state. The higher the squeezing is, the smaller the fidelity is, and the lower the classical limitation of fidelity is. The dependence of the optimum gain for teleporting a squeezed vacuum state upon the EPR entanglement is also calculated. The results obtained provide important references for designing experimental systems of teleporting a non-classical state and judging the quality of the teleported quantum state.     

实用化多功能光压缩器

激光二极管抽运的YAPKTP内腔倍频单频激光器及其抽运的半整块非简并光学参量振荡腔(NOPO)被固定在一体的殷钢底座上构成了全固化多功能光压缩器———Squeezer.通过控制不同的工作条件,在此装置上可以产生多种类型压缩光:阈值以上产生约6dB(74%)量子相关孪生光束;在阈值以下,通过注入信号光参量缩小过程产生21dB明亮正交振幅压缩光;将参量放大器出射的两个频率简并偏振垂直的孪生光束分开,获得振幅反关联位相正关联明亮EPR源. 关键词： 光压缩器 光学参量振荡腔(OPO) 全固化     

连续可调谐OPO及其在Cs2分子频率调制光谱中的应用

采用边带锁频技术,在II类相位匹配半整体光学参量振荡器(OPO)中实现双谐振OPO稳定单频运转,通过调谐抽运光频实现OPO输出连续可调谐, 最大连续调谐范围2.8GHz,将其应用于Cs2分子的频率调制光谱,观测到室温附近Cs2分子气室样品在1041.506nm附近的高分辨率光谱.     

Refractive index sensor based on a step index multimode polymer optical fiber with a micro-hole created by a miniature numerical control machine

A compact in-fiber refractive index (RI) sensor based on a step index multimode polymer optical fiber with a micro-hole drilled by a miniature numerical control machine is presented. A good linear relationship between the transmission and RI over a large operating range from 1.335 to 1.475 and a sensitivity of 36 071.43 mV/RIU (RI unit) are found. The relationship between the transmission and the RI of the hole depends on the micro-hole’s diameter and depth. The RI sensor developed in this letter is low-cost, easily fabricated, and capable of continuous measurement.     

一个8-O-4'新木脂素化合物的对映选择性合成

报道了一条立体选择性合成赤式8-O-4'新木脂素的新路线. 以Sharpless双羟化反应构筑2个手性中心, 经过几步转化, 得到关键中间体6, 通过Mitsunobu反应进行偶联, 可以得到单一赤式的8-O-4'新木脂素化合物. 通过此路线, 立体选择性地合成了一个天然8-O-4'新木脂素的赤式异构体.     

Detection of 13.8 dB squeezed vacuum states by optimizing the interference efficiency and gain of balanced homodyne detection

Squeezed states belong to the most prominent non-classical resources. They have compelling applications in precise measurement, quantum computation, and detection. Here, we report on the direct measurement of 13.8 d B squeezed vacuum states by improving the interference efficiency and gain of balanced homodyne detection. By employing an auxiliary laser beam, the homodyne visibility is increased to 99.8%. The equivalent loss of the electronic noise is reduced to 0.05% by integrating a junction field-effect transistor(JFET) buffering input and another JFET bootstrap structure in the balanced homodyne detector.