共查询到20条相似文献,搜索用时 803 毫秒
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We provide a full numerical characterization of non-Markovian quantum decoherence for a two-level (qubit) system coupled to a tailorable reservoir by studying the influence of different factors, such as system–reservoir coupling and temperature. The necessity of a decoherence analysis from short to long time ranges and for a large set of parameters are fundamental requirements for quantum information processing in order to produce a controlled conditional quantum dynamics. We show how the Feynman–Vernon influence functional technique can be used in order to obtain a numerical algorithm that enables a full characterization of non-Markovian processes. This analysis paves the way for modeling the prevention and control of decoherence in solid-state systems with ultrafast dynamics and strong environmental coupling. 相似文献
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《Applied Superconductivity, IEEE Transactions on》2009,19(1):2-13
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Programmable quantum logic gates using teleportation with non-maximally entangled states 总被引:1,自引:0,他引:1
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A scheme is proposed for involving programmable quantum logic gates via teleportation,which is a unique technique in quantum mechanics.In our scheme,considering the inevitable decoherence caused by noisy environment,the quantum states are not maximally entangled.We show the implementation of single qubit quantum gates and controlled-NOT(C-NOT) gate,which are universal quantum gates.Hence,any quantum gate can be implemented by using teleportation withnon-maximally entangled states.Furthermore,two schemes in differet connections of universal gates are proposed and compared,and our results show the parallel connection outperforms the cascade connection. 相似文献
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Ruda H.E. Bi Qiao 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2003,91(11):1874-1883
Traditional approaches to computing based on nanoelectronics will likely need to embrace quantum phenomena over the coming decade with the trend toward decreasing on-chip feature sizes. Concurrently, as resonant tunneling and single-electron-based quantum devices become more prevalent, one can expect quantum computing and quantum information based on appropriate isolated and coupled low-dimensional semiconducting systems to attract more attention. We report on work aimed at understanding the limitations on how to implement practical quantum information systems that counter the natural effects of decoherence and offer suitable approaches to control of such systems. The emphasis in this paper is on open systems. We close the paper with some remarks on possible practical schemes for fabricating such systems and identify some of the challenges that lie ahead in realizing these schemes. 相似文献
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量子秘密共享(Quantum secret sharing , QSS)可以在不完全信任的通信双方间传递密钥,是量子密码的一个重要分支。本文提出一种含有安全可信任中心的QSS方案。其中,中心能够产生并提供量子态,也能够测量并提取量子态信息。通信用户(Alice、Bob和Charlie)不拥有量子比特产生器和测量器,只需通过幺正操作和交换操作实现密钥传输和窃听防范;同时,Bob和Charlie必须合作才能获得正确的密钥。理论分析表明该方案可有效地抵御截取重发攻击、纠缠测量攻击和关联提取攻击等常见攻击策略;由于方案减少了量子比特产生器和测量器的数量,降低了量子通信的费用。这将为量子秘密共享实用化提供一种可参考的方法。 相似文献
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Hayakawa H. Yoshikawa N. Yorozu S. Fujimaki A. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2004,92(10):1549-1563
Single-flux quantum logic (SFQ) circuits, in which a flux quantum is used as an information carrier, have the possibility for opening the door to a new digital system operated at over 100-GHz clock frequency at extremely low power dissipation. The SFQ logic system is a so-called pulse logic, which is completely different from the level logic for semiconductors like CMOS, so circuit design technologies for SFQ logic circuits have to be newly developed. Recently, much progress in basic technologies for designing SFQ circuits and operating circuits at high speeds has been made. With advances in these design tools, large-scale circuits including more than several thousand junctions can be easily operated with the clock frequency of more than several tens of gigahertz. High-end routers and high-end computers are possible applications of SFQ logic circuits because of their high throughput nature and the low power dissipation of SFQ logic. In this paper, recent advances of SFQ circuit design technologies and recent developments of switches for high-end routers and microprocessors for high-end computers that are considered possible applications for SFQ logic will be described. 相似文献
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Ainhoa Urtizberea Eva Natividad Pablo J. Alonso Miguel A. Andrés Ignacio Gascón Michel Goldmann Olivier Roubeau 《Advanced functional materials》2018,28(31)
Molecular spin qubits have been shown to reach sufficiently long quantum coherence times to envision their use as hardware in quantum processors. These will however require their implementation in hybrid solid‐state devices for which the controlled localization and homogeneous orientation of the molecular qubits will be necessary. An alternative to isolated molecules that can ensure these key aspects is 2D framework in which the qubit would act as node. In this work, it is demonstrated that the isolated metalloporphyrin [Cu(H4TCPP)] molecule is a potential spin qubit, and maintains similar quantum coherence as node in a 2D [{CuTCPP}Zn2(H2O)2] metal–organic framework. Mono‐ and multilayer deposits of nanosheets of a similar 2D framework are then successfully formed following a modular method based on Langmuir–Schaefer conditions. The orientation of the {CuTCPP} qubit nodes in these nanosheets is homogeneous parallel to the substrate. These nanosheets are also formed with a control over the qubit concentration, i.e., by dilution with the unmetallated porphyrin. Eventually, 2D nanosheets are formed in situ directly on a substrate, through a simple protocol devised to reproduce the Langmuir–Schaefer conditions locally. Altogether these studies show that 2D spin qubit frameworks are ideal components to develop a hybrid quantum computing architecture. 相似文献
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Experimentation and practical work, which are usually accomplished in a laboratory, are the basics of technological fields. Laboratory activities enable students to acquire methodologies, work habits, knowledge, and experience of equipment operation, in conditions as near as possible to their future professional activities. The evolution of communication and information technologies opens new possibilities in educational methods. This article describes a project that aims to facilitate the use of real robots in an educational laboratory via Web, allowing users to learn different robotics aspects while performing a competition. Students can remotely program several robots to participate in games to accomplish a set of goals in a remote stadium (the RoboStadium). To facilitate the use of robots, the online robot stadium provides a set of training resources. Having these resources, previous knowledge on robotics is not required to use the system. Since robotics is a multidisciplinary field (mechanics, electronics, control, mathematics, computers, etc.), students of different degrees can take advantage of the presented system. Researchers of two Spanish universities are participating in this project, which provides robotics telelaboratories via Web. 相似文献
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量子通信及其应用前景 总被引:3,自引:0,他引:3
量子通信是近几年发展起来的新兴学科,具有巨大的潜在应用价值和重大的科学意义。介绍了量子通信的主要组成部分;分析了量子通信的保密、大容量、远距离传输等特点;对量子通信的应用前景进行了一定的探讨。量子通信不仅在军事、国防等领域具有重要的作用,而且会极大地促进国民经济的发展。 相似文献
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基于紧束缚模型的实空间格点组成的一维线性均匀有序的量子点阵列为研究对象,然后利用演化算符的作用使其在量子点阵列的自旋链上进行单量子比特的信息传输。即使用演化算符 使单比特量子态从量子点阵列起始端为多粒子态 传输到末端态为 ,最后在此基础上计算概率来讨论了单量子比特能从起始端的多粒子态 的第一个量子比特完全传输到态 的末端第N个量子比特是可能的。 相似文献
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Quantum computing with superconductors 总被引:2,自引:0,他引:2
Berggren K.K. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2004,92(10):1630-1638
Superconductive technology is one of the most promising approaches to quantum computing because it offers devices with little dissipation, ultrasensitive magnetometers, and electrometers for state readout, large-scale-integration, and a family of classical electronics that could be used for quantum bit (qubit) control. The challenges this technology faces, however, are substantial: for example, control of the qubit to a part in /spl sim/10/sup 4/ must be accomplished with analog control pulses. But even after this is done, the accuracy is limited by the unavoidable decay of quantum information in the system. Recent experiments suggest the time over which this decay occurs is <1 /spl mu/s, though it is expected to lengthen as experimental methods improve. A 1-/spl mu/s decay time would mandate a very difficult to achieve maximum time of /spl sim/100 ps per analog operation. Thus, quantum computing is, simultaneously a promising technology for solving certain very hard problems in computer science and a daunting challenge for those working to develop that technology. 相似文献
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量子相干与量子消相干 总被引:1,自引:1,他引:1
对经典相干和量子相干进行了探讨,介绍量子相干在量子计算和量子信息中的应用。分析几种引起量子消相干的可能原因,并利用Kraus算子和密度矩阵对一种量子消相干模型进行详细地研究。 相似文献
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Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high stability and scalability,which enables a vital platform for the implementation of quantum information processing and quantum commu-nications.This article reviews recent experimental progress and advances in the development of integrated quantum photonic devices and systems for quantum communications and quantum networks. 相似文献