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该文用Shauder不动点定理及微分不等式理论研究了一类非线性四阶常微分方程三点边值问题的存在性,并利用边界层校正法获得解及其二阶导数的高阶渐进展开式. 相似文献
3.
建立了碱消解-火焰原子吸收光谱法测定土壤中六价铬的方法.讨论了pH值对六价铬测定的影响.干扰实验的结果表明同等含量的三价铬对六价铬测定无干扰.实验对比了无背景校正、氘灯背景校正、塞曼背景校正三种工作方式,分别对低、中、高三个水平土壤六价铬标准物质进行了测定,结果表明,低含量的土壤样品用塞曼背景校正方式测定的结果更准确,... 相似文献
4.
Long Gui-lu Deng Fu-guo Wang Chuan Li Xi-han Wen Kai Wang Wan-ying 《Frontiers of Physics in China》2007,2(3):251-272
In this review article, we review the recent development of quantum secure direct communication (QSDC) and deterministic secure
quantum communication (DSQC) which both are used to transmit secret message, including the criteria for QSDC, some interesting
QSDC protocols, the DSQC protocols and QSDC network, etc. The difference between these two branches of quantum communication
is that DSQC requires the two parties exchange at least one bit of classical information for reading out the message in each
qubit, and QSDC does not. They are attractive because they are deterministic, in particular, the QSDC protocol is fully quantum
mechanical. With sophisticated quantum technology in the future, the QSDC may become more and more popular. For ensuring the
safety of QSDC with single photons and quantum information sharing of single qubit in a noisy channel, a quantum privacy amplification
protocol has been proposed. It involves very simple CHC operations and reduces the information leakage to a negligible small
level. Moreover, with the one-party quantum error correction, a relation has been established between classical linear codes
and quantum one-party codes, hence it is convenient to transfer many good classical error correction codes to the quantum
world. The one-party quantum error correction codes are especially designed for quantum dense coding and related QSDC protocols
based on dense coding.
相似文献
5.
Chi-Kwong Li 《Journal of Mathematical Analysis and Applications》2008,348(2):843-855
For a positive integer k, the rank-k numerical range Λk(A) of an operator A acting on a Hilbert space H of dimension at least k is the set of scalars λ such that PAP=λP for some rank k orthogonal projection P. In this paper, a close connection between low rank perturbation of an operator A and Λk(A) is established. In particular, for 1?r<k it is shown that Λk(A)⊆Λk−r(A+F) for any operator F with rank(F)?r. In quantum computing, this result implies that a quantum channel with a k-dimensional error correcting code under a perturbation of rank at most r will still have a (k−r)-dimensional error correcting code. Moreover, it is shown that if A is normal or if the dimension of A is finite, then Λk(A) can be obtained as the intersection of Λk−r(A+F) for a collection of rank r operators F. Examples are given to show that the result fails if A is a general operator. The closure and the interior of the convex set Λk(A) are completely determined. Analogous results are obtained for Λ∞(A) defined as the set of scalars λ such that PAP=λP for an infinite rank orthogonal projection P. It is shown that Λ∞(A) is the intersection of all Λk(A) for k=1,2,…. If A−μI is not compact for all μ∈C, then the closure and the interior of Λ∞(A) coincide with those of the essential numerical range of A. The situation for the special case when A−μI is compact for some μ∈C is also studied. 相似文献
6.
量子纠错编码技术在量子通信和量子计算领域起着非常重要的作用.构造量子纠错编码的主要方法是借鉴经典纠错编码技术,目前几乎所有经典纠错编码方案都已经被移植到量子领域中来,然而在经典编码领域纠错性能最杰出的Turbo码却至今没有量子对应.提出了一种利用量子寄存器网络构造量子递归系统卷积码的简单实现方案,同时利用量子SWAP门设计了一种高效的量子交织器门组网络方案.最后仿照经典Turbo码的设计原理提出串行级联的量子Turbo码,同时提出了可行的译码方法.量子Turbo码不仅丰富了量子纠错码研究的领域,同时为解释
关键词:
量子递归系统卷积码
量子Turbo码
量子纠错编码
量子信息 相似文献
7.
In this article we study relations between groups and quantum error correcting codes. Groups of central type are used to construct quantum error correcting codes. Both stabilizer and Clifford codes can be derived from a construction involving this kind of groups. A more general construction of Clifford codes will be given and their correcting properties will be examined using group theoretical techniques. 相似文献
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指出了教材《通信原理》在纠检错编码定理证明中存在的问题,应用n维空间的概念,将码字与n维空间中的点一一对应,并利用这种对应关系,对纠检错编码定理给予了新的证明,完善了差错控制编码理论. 相似文献
10.
(t,m,s)‐nets are point sets in Euclidean s‐space satisfying certain uniformity conditions, for use in numerical integration. They can be equivalently described in terms of ordered orthogonal arrays, a class of finite geometrical structures generalizing orthogonal arrays. This establishes a link between quasi‐Monte Carlo methods and coding theory. The ambient space is a metric space generalizing the Hamming space of coding theory. We denote it by NRT space (named after Niederreiter, Rosenbloom and Tsfasman). Our main results are generalizations of coding‐theoretic constructions from Hamming space to NRT space. These comprise a version of the Gilbert‐Varshamov bound, the (u,u+υ)‐construction and concatenation. We present a table of the best known parameters of q‐ary (t,m,s)‐nets for qε{2,3,4,5} and dimension m≤50. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 403–418, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10015 相似文献