Quantum Information and Entanglement

1.介绍

作为一种迅速扩张和跨学科的主题，量子信息已经吸引了很多关注和许多来自物理学，计算机科学，信息，数学以及最近电子工程的领先的理论家和实验主义者。虽然在1935年可以追溯到epr悖论的量子纠缠并引起关于与现实和地方的量子力学的基础的讨论，但在量子信息处理中起着至关重要的作用，如量子计算，量子传送，密集编码，量子纠错，量子加密方案，纠缠交换和远程状态准备。过去十年来看，许多引人注目的成就得到了见证。

这一特殊问题的主要重点是量子纠缠理论及其对量子信息处理的应用。作为一个国际论坛，用于总结最新的发展和想法，呈现新的结果，同时提高对该领域的量子信息理论界的此类研究的意识，该问题包括原始研究文章以及审查将刺激量子信息处理，相关物理系统和量子纠缠理论的持续努力的文章。

Among the quantum information processing quantum simulation was in fact the first proposed application for which quantum computers might give an exponential enhancement over classical computation, as was noted in 1982 by Feynman that simulating quantum dynamics on a classical computer was apparently intrinsically hard. On the other hand by the very definition of nonlocality, that is, violation of a Bell inequality, understanding the nonlocal correlations created upon measurement of some entangled quantum system is a problem that runs up against our common representation of the world. Bancal, Branciard, and Gisin propose a family of models that can simulate von Neumann measurements in theplane of the Bloch sphere on n-partite GHZ states using only bipartite nonlocal boxes. For the tripartite and fourpartite states, the models can be translated into classical communication schemes with finite average communication cost. Due to the interaction with the environment, quantum error correction is of significance in information processing. Guo, Zeng, and Lee investigate how to simplify the constructions of quantum error-correction codes via the quadratic residues. They present the quantum code that is constructed via the stabilizer formalism of an Abelian group and has advantages of being fast constructed with more efficiency than the previous quantum codes.

Quantum computing is the most important subject in quantum information processing. The operator quantum error correction encompasses active error correction and leads to improved threshold results in fault tolerant quantum computing. Qiao, Liu, and Ruda study the theory for a decoherence-free subspaces and subsystems in which quantum computing is performed in a decoherence-free subspace, although the total space still subject to a decoherence. A formalism for quantum computing in the decoherence-free subspaces is presented. The constructed subspaces are partial triangulated to the index related to the environment. The quantum states in the subspaces are just projected states which are ruled by a subdynamic kinetic equation. These projected states can be used to perform the ideal quantum logic operations without decoherence. Merkli, Berman, and Sigal describe their recent results on the resonant perturbation theory of decoherence and relaxation for quantum system with many qubits. The approach represents a rigorous analysis of the phenomenon of decoherence and relaxation for general N-level systems coupled to reservoirs of the bosonic fields. The approach does not involve master equation approximations and applies to a wide variety of systems which are not explicitly solvable. The cluster state is a special, highly entangled quantum state that forms the universal resource for performing measurement-based quantum computation. Katz and Wang give a brief review of the theoretical foundations of cluster state quantum computation and propose a scheme for the generation of such entanglement in a solid-state medium with numerical calculations on the viability of the scheme for the creation of cluster states. Another scheme related to fault tolerant quantum computing is the topological one. Kádár, Marzuoli, and Rasetti study topological quantum field theories concerning this scheme.

量子DOT是实施量子信息方案的重要候选者。量子点理论已被广泛研究。在Berthelot，Voisin，Delalande，Roussignol，Ferreira和Cassabois的审查中，它们呈现了光谱扩散的外在脱模机理的一般理论描述，其在低温下占据半导体量子点中的脱机动态。讨论了随机电报和高斯随机噪声的限制。Seigneur，Gonzalez，Leuenberger和Schoenfeld调查量子点旋转量子比特和量子网络节点内的单光子Qubit之间的缠结动态。还研究了针对各种脱机过程的相关稳健性。单个光子和单光子对等产生量子信息实施中的基础。Kumano，Ekuni，Nakajima，Idutsu，Sasakura和Semune证明了单光子和偏振相关的光子对从单个半导体量子点发射。

量子纠缠在量子信息处理中起着至关重要的角色。量子纠缠态已成为量子信息科学迅速扩大领域的关键成分。李，费和李杰斯特在量子纠缠理论中介绍了一些最近的结果：基于Bloch表示，协方差矩阵，正常形式和缠结证人的可分离标准;并发和纠结的下限和子地下性财产;完全纠缠的分数与量子传送和缠结蒸馏的最佳保真度相关。Bayat和Bose研究了使用均匀耦合的有限反铁磁性Spin-1/2 Heisenberg链作为用于传递缠结的通道的可能性。一对最大缠绕的旋转的一个构件最初将链条的一端附加到其地状态下，并且计算出该缠结的动态传播到另一端。结果表明，与其地位的铁磁链的类似方案相比，在该方案中，纠缠速度较快地传播，较少的纯度更高。此外，与铁磁盒相比，非零温度和去极化环境均发现较少的破坏性。Casado，Guerra和Plácido将Wigner功能形式主义应用于使用参数下转换中产生的极化纠缠的部分钟声分析。 Two-photon statistics at a beam-splitter are reproduced by a wavelike description with zeropoint fluctuations of the electromagnetic field.

量子信息处理基本上基于量子力学。Khrennikov讨论了EPR-Argument，一种方式从量子力学中的两个版本的投影假设的一个方式。Rocchi在最近的信息理论上介绍了一个简短的调查，并回顾了古典和量子物理学中信息概念化的一些关键票据。

这个特殊问题的访客编辑希望感谢所有提交稿件的作者考虑。还要担任担任提交的稿件裁判的许多人。

邵明飞
Sergio Albeverio
adan cabello
Naihuan Jing
Debashish Goswami

版权

版权© 2010 Shao-Ming Fei et al. This is an open access article distributed under theCreative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.