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Creating cluster states in flux qubits with XY-type exchange interactions

Physical Review A 2013年第4期88卷 044303-044303页

作者： Zu-Rong Zhang Chun-Yan Li Chun-Wang Wu Hong-Yi Dai Cheng-Zu Li College of Science National University of Defense Technology Changsha 410073 People's Republic of China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou 450000 People's Republic of China

We propose a theoretical scheme to generate flux-qubit clusters using XY interactions. In our scheme, two neighboring qubits are coupled via a dc superconducting quantum interference device (SQUID). All flux qubits are always biased at their optimal points. The XY interaction can be controlled by the bias current applied to the SQUID for the two coupled qubits with the same resonance frequencies or by the frequency of a microwave pulse applied to the SQUID for the two coupled qubits with unequal resonance frequencies. The generation of a d-dimensional cluster state needs only 2d steps. Existing technology allows us to rapidly modulate the bias current and easily control the frequency of the pulse, and thus our scheme is experimentally feasible.

关键词： Creating cluster states Scheme Bias currents Countries (nations) flux Clusters resonant frequencies microwave pulse Exchange interaction Superconducting quantum interference devices

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Interlayer vibrational modes in few-quintuple-layer Bi2Te3 and Bi2Se3 two-dimensional crystals: Raman spectroscopy and first-principles studies

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Physical Review B 2014年第24期90卷 245428-245428页

作者： Yanyuan Zhao Xin Luo Jun Zhang Junxiong Wu Xuxu Bai Meixiao Wang Jinfeng Jia Hailin Peng Zhongfan Liu Su Ying Quek Qihua Xiong Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore Institute of High Performance Computing 1 Fusionopolis Way #16-16 Connexis Singapore 138632 Singapore Department of Physics Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore 6 Science Drive 2 Singapore 117546 Singapore Center for Nanochemistry Beijing National Laboratory for Molecular Sciences (BNLMS) College of Chemistry and Molecular Engineering Peking University Beijing 100871 People's Republic of China Department of Physics Key Laboratory of Artificial Structures and Quantum Control Ministry of Education Shanghai Jiao Tong University Shanghai 200240 People's Republic of China NOVITAS Nanoelectronics Centre of Excellence School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Singapore

Layered materials, such as graphite/graphene, boron nitride, transition metal dichalcogenides, represent materials in which reduced size, dimensionality, and symmetry play critical roles in their physical properties. Here, we report on a comprehensive investigation of the phonon properties in the topological insulator Bi2Te3 and Bi2Se3 two-dimensional (2D) crystals, with the combination of Raman spectroscopy, first-principles calculations, and group theory analysis. Low frequency (<30cm−1) interlayer vibrational modes are revealed in few-quintuple-layer (QL) Bi2Te3/Bi2Se3 2D crystals, which are absent in the bulk crystal as a result of different symmetries. The experimentally observed interlayer shear and breathing mode frequencies both show blueshifts, with decreasing thickness in few-QL Bi2Te3 (down to 2QL) and Bi2Se3 (down to 1QL), in agreement with first-principles calculations and a linear chain model, from which the interlayer coupling force constants can be estimated. Besides, an intense ultralow (<12cm−1) frequency peak is observed in 2–4QL Bi2Te3, which is tentatively attributed to a substrate-induced interface mode supported by a linear chain model analysis. The high frequency Raman peaks exhibit frequency shifts and broadening from 3D to 2D as a result of the phonon confinement effect. Our studies shed light on a general understanding of the influence of dimensionality and crystal symmetry on the phonon properties in layered materials.

关键词： RAMAN spectroscopy GROUP theory CRYSTAL symmetry GRAPHITE BORON nitride TRANSITION metals PHONONS

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Stochastic Multi-Symplectic Integrator for Stochastic Nonlinear Schrodinger Equation

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Communications in Computational Physics 2013年第7期14卷 393-411页

作者： Shanshan Jiang Lijin Wang Jialin Hong College of Science Beijing University of Chemical TechnologyBeijing 100029P.R.China School of Mathematical Sciences Graduate University of Chinese Academy of SciencesBeijing 100049P.R.China State Key Laboratory of Scientific and Engineering Computing Institute of ComputationalMathematics and Scientific/Engineering ComputingAcademy of Mathematics and System ScienceChinese Academy of SciencesP.O.Box 2719Beijing 100190P.R.China

In this paper we propose stochastic multi-symplectic conservation law for stochastic Hamiltonian partial differential equations,and develop a stochastic multisymplectic method for numerically solving a kind of stochastic nonlinear Schrodinger *** is shown that the stochasticmulti-symplecticmethod preserves themultisymplectic structure,the discrete charge conservation law,and deduces the recurrence relation of the discrete *** experiments are performed to verify the good behaviors of the stochastic multi-symplectic method in cases of both solitary wave and collision.

关键词： Stochastic nonlinear Schrodinger equations stochasticmulti-symplectic Hamiltonian systems multi-symplectic integrators

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The Research on Cryptographic Algorithms Recognition Technology

The Research on Cryptographic Algorithms Recognition Technol...

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International Conference on Intelligent System Design and engineering Application (ISDEA)

作者： Rui Chang Liehui Jiang Hui Shu Yaobin Xie State Key Laboratory of Mathematic Engineering and Advanced Computing Zhengzhou Henan China

At present, the research on security of computer system and searching for malicious codes pays more attention to cryptographic algorithms recognition technology. However, the existing theories or tools in the field of cryptographic algorithms recognition are not mature. In order to improve the accuracy of cryptographic algorithms recognizing, this paper discusses encryption and decryption functions characteristic information database and proposes a recognition model to recognize cryptographic algorithms from binary files. The accuracy assessment indicates the model is effective and feasible.

关键词： Algorithm design and analysis Ciphers Databases Information entropy Encryption Accuracy

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Practical decoy-state measurement-device-independent quantum key distribution

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Physical Review A 2013年第5期87卷 052329-052329页

作者： Shi-Hai Sun Ming Gao Chun-Yan Li Lin-Mei Liang Department of Physics National University of Defense Technology Changsha 410073 People's Republic of China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou 450002 People's Republic of China State Key Laboratory of High Performance Computing National University of Defense Technology Changsha 410073 People's Republic of China

Measurement-device-independent quantum key distribution (MDI-QKD) is immune to all the detection attacks; thus when it is combined with the decoy-state method, the final key is unconditionally secure, even if a practical weak coherent source is used by Alice and Bob. However, until now, the analysis of decoy-state MDI-QKD with a weak coherent source is incomplete. In this paper, we derive, with only vacuum+weak decoy state, some tight formulas to estimate the lower bound of yield and the upper bound of error rate for the fraction of signals in which both Alice and Bob send a single-photon pulse to the untrusted third party Charlie. The numerical simulations show that our method with only vacuum+weak decoy state can asymptotically approach the theoretical limit of the infinite number of decoy states. Furthermore, the statistical fluctuation due to the finite length of date is also considered based on the standard statistical analysis.

关键词： QUANTUM states COHERENT states PHOTONS COMPUTER simulation FLUCTUATIONS (Physics) DISTRIBUTION (Probability theory)

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An Implementation of Montgomery Modular Multiplication on FPGAs

An Implementation of Montgomery Modular Multiplication on FP...

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International Conference on Information Science and Cloud computing (ISCC)

作者： Xinkai Yan Guiming Wu Dong Wu Fang Zheng Xianghui Xie State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi China State Key Lab. of Math. Eng. & Adv. Comput. Wuxi China

Modular multiplication is one of the most important operations in the public key cryptographic algorithms. In order to design a high-performance modular multiplier, we present a novel hybrid Montgomery modular multiplier over GF(p) on FPGAs, which employs Karatsuba and Knuth multiplication algorithms in different levels to implement large integer multiplication. A 9-stage pipeline full-word multiplier is proposed for the 256-bit multiplication with 4-level recursion. The performance of our modular multiplier is improved through optimizing the pipeline and reducing carry-chain latency of the modular adder. On average, our modular multiplier can perform one 256-bit modular multiplication in 3 cycles. We can integrate 13 modular multipliers on a Xilinx Virtex-6 V6VSX475T FPGA. The experimental results show that the throughput of 856.9 million modular multiplications per second can be achieved and the hybrid Montgomery modular multiplier has an outstanding performance in the situations which need continuous multiplications.

关键词： Adders Pipelines Digital signal processing Field programmable gate arrays Algorithm design and analysis Elliptic curve cryptography Table lookup

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A Java-based package for genetic algorithm

A Java-based package for genetic algorithm

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2nd International Conference on key engineering Materials and Computer Science, KEMCS 2013

作者： Qiao, Shan Ping Yan, Bao Qiang School of Management Science and Engineering Shandong Normal University Jinan 250014 China Shandong Provincial Key Laboratory of Network Based Intelligent Computing School of Information Science and Engineering University of Jinan Jinan 250022 China School of Mathematical Science Shandong Normal University Jinan 250014 China

ISBN: (纸本)9783037857274

Genetic algorithm is a very important and popular kind of algorithm of evolution computing. In order to use this algorithm better and platform-independently, this paper introduces an implement package which is coded in Java, an object-oriented and platform-independent advanced computer programming language, for genetic algorithm. This package includes several sub-packages. In each sub-package, there are some classes with different roles and functions. After the test, these classes can work properly and efficiently in together. The good effect has been received through using this algorithm in four function optimization problems. For the further goal, some studies even need to be carried out in the future. © (2013) Trans Tech Publications, Switzerland.

关键词： Genetic algorithms

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A flag simulation strategy based on fusion of semantic trees in binary translation

A flag simulation strategy based on fusion of semantic trees...

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International Conference on Fuzzy Systems and Knowledge Discovery (FSKD)

作者： Xiaonan Liu Rongcai Zhao Jianmin Pang Meijuan Yin Lili Bai Wuping Chen State Key Laboratory or Mathematics Engineering and Advanced Computing Zhengzhou China Science and Technology on Information Assurance Laboratory Beijing China

ISBN: (纸本)9781467352512

Binary translation is the emulation of one instruction set by another through translation of code. Sequences of instructions are translated from the source to the target instruction set. The semantic equivalence conversion of instructions is the core of a binary translation system. In order to simulate the behavior of a program on the target platform more accurately, the change of the special state register must be exactly simulated. A flag register simulation strategy based on fusion of semantic trees is presented in this paper. First, it is determined whether the instructions meet some special conditions by the relations among instruction semantic trees. Then these instructions will be fused if the conditions are met. Finally, binary translation is carried out on the fused instructions. The experimental results show that the proposed binary translation strategy is effective. The strategy can not only reduce the problem of code inflation, but also improve the execution efficiency of the translated code.

关键词： Semantics Vegetation Optimization Registers Software Linux Computers

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An improved affinity propagation clustering algorithm for large-scale data sets

An improved affinity propagation clustering algorithm for la...

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International Conference on Natural Computation (ICNC)

作者： Xiaonan Liu Meijuan Yin Junyong Luo Wuping Chen State Key Laboratory or Mathematics Engineering and Advanced Computing Zhengzhou China Science and Technology on Information Assurance Laboratory Beijing China

Affinity Propagation (AP) clustering does not need to set the number of clusters, and has advantages on efficiency and accuracy, but is not suitable for large-scale data clustering. To ensure both a low time complexity and a good accuracy for the clustering method of affinity propagation on large-scale data clustering, an improved AP clustering algorithm named hierarchical affinity propagation (HAP) is proposed, which clusters data points by using AP algorithm several times on different level data. The data set to be clustered is firstly divided into several subsets, each of which can be efficiently clustered by AP algorithm. Then, the AP algorithm is performed on each subset to respectively select cluster centers of each subset. Further, AP clustering was again implemented on all the local cluster centers to select well-suited global exemplars of whole data set. Finally, to efficiently and accurately cluster data points in a large-scale, all the data points are clustered by the similarities between each data point and the global exemplars. The experimental results on real and simulated data sets show that, compared with the traditional AP and adaptive AP algorithm, the HAP algorithm can greatly reduce the clustering time consumption with a relatively better clustering results.

关键词： Clustering algorithms Partitioning algorithms Algorithm design and analysis Indexes Memory management Availability Computers

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Parallelizing Sparse LU Decomposition on FPGAs

Parallelizing Sparse LU Decomposition on FPGAs

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11th International Conference on Field-Programmable Technology (FPT)

作者： Wu, Guiming Xie, Xianghui Dou, Yong Sun, Junqing Wu, Dong Li, Yuan State Key Laboratory of Mathematical Engineering and Advanced Computing China

ISBN: (纸本)9781467328463;9781467328449

Sparse LU decomposition is the core computation in the direct method that solves sparse systems of linear equations. Only little work has been conducted on parallelizing it on FPGAs. In this paper, we study parallelization strategies for sparse LU decomposition on FPGAs. We first analyze how to parallelize the right-looking algorithm and find that this algorithm is not suitable for FPGAs. Then the left-looking algorithm is analyzed and considered as better candidate than the right-looking version. Our design derived from the left-looking algorithm is based on a simple yet efficient parallel computational model for FPGAs. Our design mainly consists of multiple parallel processing elements (PEs). A total of 14 PEs can be integrated into a Xilinx Virtex-5 XC5VLX330. Unlike related work, where their designs are applied to sparse matrices from particular application domains, our hardware design can be applied to any symmetric positive definite or diagonally dominant matrices.

关键词： Sparse matrices Random access memory Algorithm design and analysis Parallel processing Field programmable gate arrays Matrix decomposition Hardware

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