"Spectral implementation" for creating a labeled pseudo-pure state and the Bernstein-Vazirani algorithm in a four-qubit nuclear magnetic resonance quantum processor

A quantum circuit is introduced to describe the preparation of a labeled pseudo-pure state by multiplet-component excitation scheme which has been experimentally implemented on a 4-qubit nuclear magnetic resonance quantum processor. Meanwhile, we theoretically analyze and numerically investigate the low-power selective single-pulse implementation of a controlled-rotation gate, which manifests its validity in our experiment. Based on the labeled pseudo-pure state prepared, a 3-qubit Bernstein-Vazirani algorithm has been experimentally demonstrated by spectral implementation. The "answers" of the computations are identified from the split peak positions in the spectra of the observer spin, which are equivalent to projective measurements required by the algorithms.     

Preparation of pseudo-pure states by line-selective pulses in nuclear magnetic resonance

An alternative method of preparing the pseudo-pure state of a spin system for quantum computation in liquid-state nuclear magnetic resonance (NMR) is demonstrated experimentally. Applying specific line-selective pulses with appropriately chosen flipping angles simultaneously and then a field gradient pulse we acquire straightforwardly all pseudo-pure states for two qubits in a single experiment quite efficiently. The signal intensity from the pseudo-pure state prepared in this way is the same as that of temporal averaging. As an example of an application, a highly structured search algorithm – Hogg's algorithm – is also performed on the pseudo-pure state |0 0 prepared by the method.     

我国航空工业中结构分析通用软件的发展及应用前景

简要介绍了国外几个在航空工业中应用的著名结构分析通甩软件的发展情况和趋势,回顾了我国航空工业中结构分析通用软件的发展过程,以表格形式给出我国航空工业部门结构分析软件在运行环境、功能、性能、材料、载荷、前后置处理和用户界面等方面和国外同类软件的比较,和从设计部门对结构分析软件的要求,提出了结构分析通用软件在航空工业中的发展方向和前景。     

松香脂液的超声波清洗

本文介绍在松香加工工艺中，应用超声地脂液进行处理，使时脂液和悬浮在脂液中的细微杂质粒子得以充分洗涤和更快分离，从而达到提高松香质量的目的。     

喀纳斯自然保护区苔藓植物的调查研究

位于新疆北部阿尔泰山的喀纳斯自然景观保护区内的苔藓植物以前尚未详细调查。本文根据1980年至1988年间对该地区的三大考察研究,首次报道了该地区有苔藓植物27科、52属、77种(不含种下等级)。其次,对该地区藓苔植物属的区系成分作了分析,并初步探讨了该地区苔藓植物的群落特点。     

求解凸二次规划问题的势下降内点算法

1　引　言二次规划问题的求解是数学规划和工业应用等领域的一个重要课题 ,同时也是解一般非线性规划问题的序列二次规划算法的关键 .求解二次规划问题的早期技术是利用线性规划问题的单纯形方法求解二次规划问题的 KKT最优性必要条件[1 ] .这类算法比较直观 ,但在处理不等式约束时 ,松弛变量的引进很容易导致求解过程的明显减慢 .有效集策略是求解二次规划问题的另一类主要技术 .这类方法一般都是稳定的 ,但随着问题中大量不等式约束的出现 ,其收敛速度将越来越低[2 ] .简约空间技术将所求问题的 Hessian阵投影到自由变量所在的子空间中 …     

列阵均匀照明系统的优化设计

 结合理论分析和神光系列装置均匀照明系统的设计和实验经验, 从光的衍射、干涉与光束质量等角度分析了由透镜或衍射光学元件组成的列阵大焦斑均匀照明系统参数与靶 面焦斑强度分布的关系, 提出了列阵系统的优化设计方法。     

光束截面的动量守恒及动量衍射发散度

在忽略了瞬逝波的条件下，证明真空中单色标量光场的光束截面的动量及其任一分量都与轴向坐标无关，为守恒量；文中还给出了动量衍射发散度的表达式。     

A general templated method to homogeneous and composition-tunable hybrid TiO2 nanocomposite fibers

Sequential impregnations of metal ions and titanium tetraisopropoxide (TTIP) into activated carbon fibers (ACF) followed by a solvothermal treatment has been found to be a general method in the preparations of homogeneous and composition-tunable hybrid TiO(2) hierarchical nanocomposite fibers like WO(3)/TiO(2), Fe(2)O(3)/TiO(2) and SnO(2)/TiO(2).     

Sr2+含量对红色荧光粉Ca0.85-xSrxMoO4:Eu3+0.075,Li+0.075发光性能的影响

采用溶胶-凝胶法制备了Ca0.85-xSrxMoO4:Eu3+0.075,Li+0.075(x=0,0.05,0.1,0.15,0.2,0.3,0.4)系列红色荧光粉.对样品前驱体的热重分析表明:温度升高到540℃后样品质量基本上保持稳定,不再发生失重现象;此外,还对样品的结构和发光性能进行表征,实验结果表明:适量Sr2+取代部分的Ca2+不但没有改变Ca0.85MoO4:Eu3+,Li+的物相结构,而且明显提高了荧光粉Ca0.85MoO4:Eu3+,Li+的相对发光强度,其主要是由于加入少量的Sr2+使晶体发生了畸变,从而导致发光强度的增加.实验结果表明,Sr2+的最佳掺杂量为15%(原子分数).