From Dirac to Diffusion: Decoherence in Quantum Lattice Gases

We describe a model for the interaction of the internal (spin) degree of freedom of a quantum lattice-gas particle with an environmental bath. We impose the constraints that the particle-bath interaction be fixed, while the state of the bath is random, and that the effect of the particle-bath interaction be parity invariant. The condition of parity invariance defines a subgroup of the unitary group of actions on the spin degree of freedom and the bath. We derive a general constraint on the Lie algebra of the unitary group which defines this subgroup, and hence guarantees parity invariance of the particle-bath interaction. We show that generalizing the quantum lattice gas in this way produces a model having both classical and quantum discrete random walks as different limits. We present preliminary simulation results illustrating the intermediate behavior in the presence of weak quantum noise     

Multiple RF Coil Nuclear Magnetic Resonance Quantum Computing

Recent work has demonstrated the feasibility of using an array of quantum information processors connected via classical channels (type II quantum computer) to implement a quantum lattice-gas algorithm. This paper describes work towards constructing a new experimental set-up for a type II quantum computer. This set-up has new hardware and software specifications but does follow previously published approaches of operation encoding the initial mass density onto a twoqubit processor and using standard pulse techniques to step through the algorithm. New hardware for this system includes the ability to read both qubits at once, effectively reducing the processing time by twofold. Hardware changes also include the use of multiple coils controlled by a single spectrometer and a hardware switch. New software includes a top level control system for the spectrometer for quick experimental configuration as well as configurable modeling software to verify results. Results are presented here from a system with the final software implementations and the two channel spectrometer configuration run on a single prototype coil. Progress towards the final multi-coil implementation is described.     

量子计算的研究与应用

对量子计算的最新研究方向进行了介绍,简述了量子计算和量子信息技术的重要应用领域。分析了量子计算机与经典计算机相比所具有的优点和目前制约量子计算机应用发展的主要因素,最后展望了其未来发展趋势。     

Experimental Concatenation of Quantum Error Correction with Decoupling

We experimentally explore the reduction of decoherence via concatenating quantum error correction (QEC) with decoupling in liquid-state NMR quantum information processing. Decoupling provides an efficient means of suppressing decoherence from noise sources with long correlation times, and then QEC can be used more profitably for the remaining noise sources. PACS: 03.67.Lx, 03.65.Bz     

Relativistic Path Integral as a Lattice-based Quantum Algorithm

We demonstrate the equivalence of two representations of many-body relativistic quantum mechanics: the quantum lattice-gas method and the path integral method. The former serves as an efficient lattice-based quantum algorithm to simulate the space-time dynamics of a system of Dirac particles. Jeffrey Yepez: This discrete path integral formalism, included in the beginning of this paper, was presented on August 20, 2004 as an invited talk entitled “Lattice-based quantum algorithms for computational phsyics” at the 13th International Conference on the Discrete Simulation of Fluid Dynamics, hosted by Tufts University in Cambridge, Massachusetts. The quantum algorithm for the Dirac system in 3+1 dimensions, included at the end of this paper, was presented on May 9, 2002 at the Quantum Computation for Physical Modeling Workshop 2002, hosted by the Air Force Research Laboratory in Edgartown, Massachusetts.     

基于格的大数据动态存储完整性验证方案

文章提出了一种基于格的大数据动态存储完整性验证方案,方案基于量子计算机也难以破解的格上困难问题,具有较高的安全性,采用了Merkle哈希树技术,支持数据动态变化,并且运行效率也很高。最后文章论证了方案的正确性和安全性,该方案能够广泛的应用到与大数据动态完整性验证相关的场景中。     

基于经典存储器的量子计算机存储系统

量子计算机具有许多与经典计算机不同的量子特性,其性能远远优于经典计算机,但量子力学特有的性质也使得量子计算机的设计方法不同于经典计算机。在量子计算机中应用经典计算机的存储层次将会遇到一些前所未有的困难,文章提出了一种解决方案,以便能够在量子计算机的存储系统中应用与经典计算机类似的层次结构来提高访存性能。最后,文章给出了这种层次结构下访存性能的分析结果,指出了在何种条件下才能最大程度地发挥层次结构的性能。     

Experimental Simulation of Spin Squeezing by Nuclear Magnetic Resonance

We report on the experimental simulation of spin squeezing using a liquid-state nuclear magnetic resonance (NMR) quantum information processor. This was done by identifying the energy levels within the symmetric subspace of a system of n spin-1/2 nuclei with the energy levels of the simulated spin-(n/2) system. The results obtained for our simulations of spin-1 and spin-3/2 systems are consistent with earlier theoretical studies of spin squeezing, and illustrate interesting relations between the degree of squeezing and the strength of the correlations among the underlying spin-1/2 particles.     

量子计算机进入实验阶段

首先简要介绍分层计算的制约;其次介绍最近量子信息的开发,在理论和实践两方面的通信和计算,诸如量子逻辑门、量子密码学、量子交缠性、超距传输的实验性实现、量子算法的首次实验性实现、量子因子分解、量子纪错码以及基于硅片的原子自旋量子计算机;最后讨论克服非相干性困难的方法。     

On the Interpretation of Energy as the Rate of Quantum Computation

Over the last few decades, developments in the physical limits of computing and quantum computing have increasingly taught us that it can be helpful to think about physics itself in computational terms. For example, work over the last decade has shown that the energy of a quantum system limits the rate at which it can perform significant computational operations, and suggests that we might validly interpret energy as in fact being the speed at which a physical system is “computing,” in some appropriate sense of the word. In this paper, we explore the precise nature of this connection. Elementary results in quantum theory show that the Hamiltonian energy of any quantum system corresponds exactly to the angular velocity of state-vector rotation (defined in a certain natural way) in Hilbert space, and also to the rate at which the state-vector’s components (in any basis) sweep out area in the complex plane. The total angle traversed (or area swept out) corresponds to the action of the Hamiltonian operator along the trajectory, and we can also consider it to be a measure of the “amount of computational effort exerted” by the system, or effort for short. For any specific quantum or classical computational operation, we can (at least in principle) calculate its difficulty, defined as the minimum effort required to perform that operation on a worst-case input state, and this in turn determines the minimum time required for quantum systems to carry out that operation on worst-case input states of a given energy. As examples, we calculate the difficulty of some basic 1-bit and n-bit quantum and classical operations in an simple unconstrained scenario     

一种高效、容错的通用量子计算机体系结构

通用量子计算(universal quantum computer)在求解某些在经典计算机上具有超多项式复杂度的问题方面存在着潜在的巨大优势.通用量子计算机体系结构在很大程度上影响量子计算功效和量子程序设计风格.文中提出一种通用量子计算机的体系结构,并考虑了在该体系结构下计算能力的扩展和容错性能等问题.     

基于CFX的某型航空发动机燃气涡轮特性计算

使用CFX软件对某型航空发动机的燃气涡轮进行特性仿真计算,计算结果表明,该燃气涡轮性能平坦、工作范围宽,能满足某型发动机的设计指标。仿真计算结果可以为发动机的改进设计提供重要的参考。     

基于优化的量子门节点神经网络的煤与瓦斯突出预测

为了精准地预测煤与瓦斯突出风险等级,提出了一种基于子维进化的粒子群优化算法(sdPSO)和量子门节点神经网络(QGNN)的瓦斯突出风险等级预测模型sdPSO-QGNN.利用灰色关联分析(GRA)对突出影响因素进行降维处理,将筛选出的主控因素作为QGNN的输入,利用sdPSO对量子门节点神经网络参数进行优化,以提高量子门节点神经网络的全局与局部搜索能力,建立sdPSO-QGNN的瓦斯突出风险等级预测模型,实现对瓦斯突出风险的预测.实验结果表明,与BP(back propagation)神经网络、对称Alpha稳定分布的概率神经网络(SαS-PNN)、免疫粒子群算法优化的支持向量机(IPSO-SVM)、Memetic算法优化的极限学习机(Memetic-ELM)等预测模型相比,所提方法在提升模型泛化能力、提高预测精度方面效果显著.     

Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

A detailed analysis of the electrical response of In0.3Ga0.7As surface quantum dots (SQDs) coupled to 5-layer buried quantum dots (BQDs) is carried out as a fun...     

气体传感器计算机测试系统的研制

标定气体传感器的电性能参数,对于其理论研究和应用都具有重要的意义。文章采用计算机打印口来实现计算机和外部电路的信号控制和数据传输,具体包括温度控制、数据采集及气体配置,并采用VC＋＋6.0开发出了基于计算机打印口的应用软件程序。     

基于单片机的智能煤矿瓦斯监控系统的设计

为解决我国中小型煤矿存在的安全隐患问题,及时准确地检测瓦斯含量,提出了基于单片机的智能煤矿瓦斯监控系统;设计了智能瓦斯传感器系统,并采用微型计算机处理技术,提出了一种独特的、简便易行的软硬件设计方法;该系统减少了硬件电路的复杂程度以及不必要的人工操作,提高了系统工作的可靠性,降低了煤矿瓦斯监测系统成本,可适应中小型煤矿的要求;经过临沂矿务局在枣庄一施工基地实验及不断调试证明,该系统具有可靠性高、功能强以及经济实用等特点。     

汽车气制动阀类综合性能检测系统的设计

该测试系统是根据国家汽车行业相关标准,主要针对汽车气制动总阀、继动阀、弹簧制动气室、手阀、调压阀等产品性能进行综合测试的试验设备。测试项目全面,采用计算机控制和机电一体化技术,保证检验的精确性和测试数据的准确性。     

焦炉集气管压力计算机控制系统

分析了焦炉集气管压力系统非线性模型，归纳整理出１００多条具有自适应能力和多变量解耦功能的控制规则，构成控制算法库     

一种智能型煤气监控系统的设计

由于煤气泄漏具有巨大的危害性,需要对煤气泄漏进行实时的精确监控。文中介绍的一种智能型煤气监控系统具有报警限设定、声光报警、现场浓度动态显示、误差自动校正功能,而且具有自动关闭煤气管道阀门、向上位机报警、按键开启阀门的功能。该系统经过多次运行,精确度、灵敏度和稳定性均达到设计要求,且造价更低,操作更加方便。