Controlled exchange interaction between pairs of neutral atoms in an optical lattice

Ultracold atoms trapped by light offer robust quantum coherence and controllability, providing an attractive system for quantum information processing and for the simulation of complex problems in condensed matter physics. Many quantum information processing schemes require the manipulation and deterministic entanglement of individual qubits; this would typically be accomplished using controlled, state-dependent, coherent interactions among qubits. Recent experiments have made progress towards this goal by demonstrating entanglement among an ensemble of atoms confined in an optical lattice. Until now, however, there has been no demonstration of a key operation: controlled entanglement between atoms in isolated pairs. Here we use an optical lattice of double-well potentials to isolate and manipulate arrays of paired (87)Rb atoms, inducing controlled entangling interactions within each pair. Our experiment realizes proposals to use controlled exchange coupling in a system of neutral atoms. Although 87Rb atoms have nearly state-independent interactions, when we force two atoms into the same physical location, the wavefunction exchange symmetry of these identical bosons leads to state-dependent dynamics. We observe repeated interchange of spin between atoms occupying different vibrational levels, with a coherence time of more than ten milliseconds. This observation demonstrates the essential component of a neutral atom quantum SWAP gate (which interchanges the state of two qubits). Its 'half-implementation', the root SWAP gate, is entangling, and together with single-qubit rotations it forms a set of universal gates for quantum computation.     

Biosynthesis of animal and plant bufadienolides. Parallel experiments with pregn-5-en-3-ß-ol-20-one-20-14C inScilla maritima andBufo paracnemis

Zusammenfassung Pregnenolon-20-¹⁴C wird von roten Meerzwiebeln als Vorstufe für herzwirksame Glykoside verwendet, dagegen kannBufo paracnemis diese Produkte, subkutan appliziert, nicht in die üblichen Krötengifte überführen.     

企业研发团队知识共享影响因素的实证研究

基于知识共享理论和研发团队知识共享特征和影响因素,提出企业研发团队知识共享影响因素概念模型及理论假设,并运用调查问卷和结构方程模型对研发团队知识共享影响因素进行实证研究.结果表明,知识提供者、接受者、共享手段和共享双方关系4因素对研发团队知识共享水平有显著影响,而知识共享文化对知识共享水平影响作用不显著.提出了提高企业研发团队知识共享水平的对策与建议.     

基于Simulink的动态电路分析

介绍了Simulink应用于动态电路仿真分析的方法,以一个实例详述了图形输入式建模、参数设置、仿真配置、Matlab绘图分析等步骤．指出了联合运用To File、To Workspace和Scope模块,实现不同参数情况下仿真分析的优越性．     

数学分析在高等代数中的某些应用

高等代数中的某些问题,若用代数学的方法解决起来可能相当繁琐,但若结合数学分析的方法,则问题往往会迎刃而解．该文使用数学分析中的函数连续性和无穷区间的广义积分知识解决某些矩阵问题和二次型问题．     

Biosynthesis of the bufadienolide marinobufagin in toadsBufo paracnemis from cholesterol-20-14C

Zusammenfassung Der biogenetische Ursprung des Marinobufagins in KrötenBufo paracnemis wurde durch Injektion von Cholesterol-20-¹⁴C nachgewiesen. Durch Abbau wurde festgestellt, dass die Gesamtaktivität des Produktes im C-20 des Marinobufagins enthalten ist.     

MATLAB应用于离散时间系统分析的教学探讨

在离散时间系统分析的课堂教学中，借助科学计算软件MATLAB能在阐述概念的同时。避免过多的手动运算，即时给出相关结果和函数图形，使得在有限的时间内展现整个系统分析的流程，节省了时间，改善了授课效果．     

The Concept of Sustainable Development Revisited

The concept of sustainable development is here revised in the light of a brief historical analysis, followed by a semantic analysis of the expressions development and sustainability. The authors criticize the common use of this concept in a loose way or in wide generalizations, to conclude, based on the principles of human ecology, that it is only possible to make it operational in limited spans of time and in limited spatial units.