Efficient scheme for entangled states and quantum information transfer with trapped atoms in a resonator

A protocol is proposed to generate atomic entangled states and implement quantum information transfer in a cavity quantum electrodynamics system. It utilizes Raman transitions or stimulated Raman adiabatic passages between two systems to entangle the ground states of two three-state Λ-type atoms trapped in a single mode cavity. It does not need the measurements on cavity field nor atomic detection and can be implemented in a deterministic fashion. Since the present protocol is insensitive to both cavity decay and atomic spontaneous emission, it may have some interesting applications in quantum information processing.     

Observation of multi-Raman gain resonances in rubidium vapor

We present an experimental study of multi-Raman gain resonances in a hot rubidium vapor.The experiment is performed based on a high-efficiency four-wave mixing process due to the Raman-driven coherence in a double-A configuration.The Raman gain resonance for ~(85)Rb atoms under a bias magnetic field is shown to be split into five or six peaks,depending on the orientation of the magnetic field.The formed multi-Raman gain resonances have potential applications in measurement of magnetic fields and generation of multi-frequency correlated twin beams.     

Ultrafast optical beam deflection in a pump probe configuration

Propagation of a signal beam in an Al Ga As/Ga As waveguide multiple-prism light deflector is theoretically investigated by solving the scalar Helmholtz equation to obtain the dependences of the temporal and spatial resolvable characteristics of the ultrafast deflector on the material dispersion of Ga As including group velocity dispersion and angular dispersion,interface reflection,and interface scattering of multiple-prism deflector.Furthermore,we experimentally confirm that,in this ultrafast beam deflection device,the deflecting angle of the signal light beam is linear with the pump fluence and the temporal resolution of the ultrafast deflection is 10 ps.Our results show that the improvement of the temporal and spatial resolvable performances is possible by properly choosing the structural parameters and enhancing the quality of the device.     

Realization of quantum permutation algorithm in high dimensional Hilbert space

Quantum algorithms provide a more efficient way to solve computational tasks than classical algorithms. We experimentally realize quantum permutation algorithm using light's orbital angular momentum degree of freedom. By exploiting the spatial mode of photons, our scheme provides a more elegant way to understand the principle of quantum permutation algorithm and shows that the high dimension characteristic of light's orbital angular momentum may be useful in quantum algorithms. Our scheme can be extended to higher dimension by introducing more spatial modes and it paves the way to trace the source of quantum speedup.     

非晶和纳米ZrO_2·Y_2O_3(15%)的X射线衍射与扩展X射线吸收精细结构研究

利用粉末X射线衍射和扩展X射线吸收精细结构(EXAFS)技术对用化学共沉淀法制备的非晶和纳米ZrO2*15%Y2O3体系进行了研究.粉末X射线衍射结果表明,300℃温度处理的样品呈非晶态,500℃时样品已经晶化,形成单一立方相的纳米结构.EXAFS分析显示,在从非晶态向纳米结构晶化的过程中,最近邻的Zr-O配位层的配位数和键长没有发生明显的改变,说明300℃时已经形成和900℃相同的最近邻局域结构.而对于Zr-Zr(Y)配位层,随着晶粒尺寸的减小,配位数明显降低,键长显著缩短,具有比Zr-O配位层更大的无序.这些结果表明晶粒尺寸的变化对于较远配位层的影响要比对最近邻的影响大得多.     

量子干涉效应对原子共振荧光非经典特性的影响

研究了两个自发辐射路径之间的量子干涉效应对V型三能级原子压缩谱和光子反聚束效应的影响 .结果表明 ,量子干涉可以加强压缩效应和展宽出现压缩的相位角分量的范围 ,但却会减弱反聚束效应.Phase-dependent squeezing spectrum and photon antibunching of resonance fluorescence from a three-level V-type atom driven by a coherent field are investigated. We show that for weak excitation intensities quantum interference can greatly enhance squeezing and change the phase quadrature at which the maximum squeezing occurs. We also notice that the maximum squeezing can appear not only in either the in-phase or the out-of-phase quadrature but also in any phase quadrature, and at which phase quadrature...     

量子系统的动力学对称性研究与代数动力学

文章介绍了量子系统的动力学对称性理论和代数动力学在人造了系统和量子光学系统中的应用。     

第八届全国量子光学学术报告会简讯

１９９８年１０月８日至１１日,第八届全国量子光学学术报告会在西安交通大学召开,本届会议由中国物理学会量子光学专业委员会主办,西安交通大学理学院承办．来自包括香港在内的全国近３０个高等学校及研究所的７５名代表参加了这次会议．会议组织了５个大会特邀报告：...     

Efficient generation of non-classical photon pairs in a hot atomic ensemble

We demonstrate the generation of non-classical photon pairs in a warm ~(87)Rb atomic vapor cell with no buffer gas or polarization preserving coatings via spontaneous four-wave mixing. We obtain the photon pairs with a 1/e correlation time of 40 ns and the violation of Cauchy–Schwartz inequality by a factor of 23±3. This provides a convenient and efficient method to generate photon pair sources based on an atomic ensemble.     

非晶和纳米ZrO2,ZrO2:Y发光研究

利用共沉淀法制备了非晶和纳米ZrO2和ZrO2:Y(7%)。通过X射线衍射对其晶化过程的结构变化进行了表征，并在不同温度和气氛下进行处理，研究了对其发光性质的影响。结果表明发射谱由一个Gaussian带（峰值2．69eV)和一个非对称带（峰值3.12eV）构成，它们对应的发光中心分别为F^ 心和（F－F）^ 心。非晶样品的发光强度比纳米晶样品强，发光强度主要受氧空位的浓度和晶粒尺寸的影响，随着处理温度的升高，两者竞争的结果综合地影响了发光强度。