共查询到20条相似文献,搜索用时 93 毫秒
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提出了一种简单高效的方案,用以克服量子计算中的消相干,该方案本质性地利用了消相干过程中的合作效应及相干保持态.文章阐明了该方案的主要思想. 相似文献
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研究开放量子系统的量子耗散动力学对于理解许多新奇量子现象背后的机制和实现量子器件的精确量子态控制具有重要意义. 级联运动方程方法已成为研究这类量子耗散动力学最常用的数值方法之一. 然而,在处理强电子关联系统时,准确描述强关联效应需要高的级联截断层数. 这导致级联运动方程方法需要耗费大量物理内存和计算时间. 为了解决该问题,将具有最快耗散速率的耗散模式与其他较慢的耗散模式分离,提出了一种级联运动方程的绝热截断方案. 在单杂质安德森模型上进行的数值测试表明,与传统的方案相比,该截断方案显著地降低了级联运动方程收敛需要的截断层数. 此外,该截断方案缓解了长时间耗散动力学中的数值不稳定性. 相似文献
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量子阱非线性光学研究进展 总被引:1,自引:0,他引:1
综述了量子阱非线性光学领域近年来实验工作的进展,重点介绍了共振增强的二阶和三阶非线性效应、光折变效应、量子阱光调制器和IV族材料的非线性过程,指出该领域发展迅速,应用前景十分广阔。 相似文献
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量子计量是超冷原子气体研究中的一个热点领域.超冷原子体系独特的量子性质(量子纠缠)和量子效应有助于大幅度提高待测物理量的测量精度,这已经成为量子精密测量中的共识.量子Fisher信息对该领域的发展起了非常重要的作用.本文首先介绍量子Fisher信息的基本概念和量子计量的主要内容;然后简要回顾这些理论在提高测量精度方面的应用,特别是多粒子量子纠缠态的产生及其判定;再介绍线性和非线性原子干涉仪的相关进展;最后论述量子测量过程中的统计方法的研究进展. 相似文献
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半导体微结构物理效应及其应用讲座 第2讲 量子阱、超晶格物理及其在光电子领域中的应用 总被引:1,自引:0,他引:1
文章介绍了半导体量子阱、超晶格的基本物理,以及它在光电子领域中的应用,包括量子阱、量子线、量子点、激光器、光调制器、自电光效应器件、量子点器件等. 相似文献
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N.A. Gromov D.B. Efimov I.V. Kostyakov V.V. Kuratov 《Czechoslovak Journal of Physics》2004,54(11):1297-1303
Quantum planes, which correspond to all one-parameter solutions of Quantum Yang-Baxter Equation (QYBE) for the two-dimensional case of GL-groups, are summarized and their geometrical interpretations are given. It is shown that the quantum dual plane is associated with an exotic solution of QYBE and the well-known quantum h-plane may be regarded as the quantum analog of the flag (or fiber) plane. Contractions of the quantum supergroup G
L
q
(12) and corresponding quantum superspace C
q
(12) are considered in Cartesian basis. The contracted quantum superspace C
h
(12);) is interpreted as the non-commutative analog of the superspace with the fiber odd part. 相似文献
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Quantum Computational Logic 总被引:1,自引:0,他引:1
S. Gudder 《International Journal of Theoretical Physics》2003,42(1):39-47
A quantum computational logic is constructed by employing density operators on spaces of qubits and quantum gates represented by unitary operators. It is shown that this quantum computational logic is isomorphic to the basic sequential effect algebra [0, 1]. 相似文献
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The class of quantum languages Q() over an alphabet is the class of languages accepted by quantum automata. We study properties of Q() and compare Q() with the class of regular languages R(). It is shown that Q() is closed under union, intersection, and reversal but is not closed under complementation, concatenation, or Kleene star. It is also shown that Q() and R() are incomparable. Finally, we prove that L Q() if and only if L admits a transition amplitude function satisfying a certain property and a similar characterization is given for R(). 相似文献
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S. A. Selesnick 《International Journal of Theoretical Physics》2003,42(3):383-426
In this paper we introduce a minimal formal intuitionistic propositional Gentzen sequent calculus for handling quantum types, quantum storage being introduced syntactically along the lines of Girard's of course operator !. The intuitionistic fragment of orthologic is found to be translatable into this calculus by means of a quantum version of the Heyting paradigm. When realized in the category of finite dimensional Hilbert spaces, the familiar qubit arises spontaneously as the irreducible storage capable quantum computational unit, and the necessary involvement of quantum entanglement in the quantum duplication process is plainly and explicitly visible. Quantum computation is modelled by a single extra axiom, and reproduces the standard notion when interpreted in a larger category. 相似文献
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Carlton M. Caves Christopher A. Fuchs Pranaw Rungta 《Foundations of Physics Letters》2001,14(3):199-212
We consider entanglement for quantum states defined in vector spaces over the real numbers. Such real entanglement is different from entanglement in standard quantum mechanics over the complex numbers. The differences provide insight into the nature of entanglement in standard quantum theory. Wootters [Phys. Rev. Lett.
80, 2245 (1998)] has given an explicit formula for the entanglement of formation of two qubits in terms of what he calls the concurrence of the joint density operator. We give a contrasting formula for the entanglement of formation of an arbitrary state of two rebits, a rebit being a system whose Hilbert space is a 2-dimensional real vector space. 相似文献
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In the Fock space semantics, meanings of sentences are identified with density operators of the (unsymmetrized) Fock space
based on the Hilbert space ℂ2. Generally, the meaning of a sentence is smeared over different sectors of
. The standard quantum computational semantics is a limit case of the Fock space semantics, where the meaning of any sentence
α only “lives” in one sector of
, which is determined by the logical complexity of α. We prove that the global Fock space semantics and the standard quantum computational semantics characterize the same logic.
PACS: 03.67.Lx. 相似文献
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We spell out a demonstration that, within the framework of quantum field theory, no faster-than-light communication can be established between observers. The steps of the demonstration are detailed enough to pinpoint which properties of the theory have been misinterpreted in previous papers claiming the existence of effects that could permit such communication. The developments described here can also be used to analyze future papers making similar claims.1. This work was supportd by the U. S. Department of Energy under Contract No. DE-AC03-76SF00098.2. In the literature, communication between observers is often referred to as signaling, transmission of a signal, or exchange of information.3. Ref. 3 is an elaboration on a previous paper by the same author [25], whose results were already generalized in Refs. 26 and 27.4. In Ref. 25, it is stated that, if a particle is definitely inV
S
at timet = 0, it cannot have a zero probability to be inV
R
at two arbitrary but different times, which we callT
0 andT. We takeT
0 = 0 for simplicity. 相似文献
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We show that it is possible to associate univocally with each given solution of the time-dependent Schrödinger equation a particular phase flow (quantum flow) of a non-autonomous dynamical system. This fact allows us to introduce a definition of chaos in quantum dynamics (quantum chaos), which is based on the classical theory of chaos in dynamical systems. In such a way we can introduce quantities which may be appelled quantum Lyapunov exponents. Our approach applies to a non-relativistic quantum-mechanical system of n charged particles; in the present work numerical calculations are performed only for the hydrogen atom. In the computation of the trajectories we first neglect the spin contribution to chaos, then we consider the spin effects in quantum chaos. We show how the quantum Lyapunov exponents can be evaluated and give several numerical results which describe some properties found in the present approach. Although the system is very simple and the classical counterpart is regular, the most non-stationary solutions of the corresponding Schrödinger equation are chaotic according to our definition. 相似文献
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本文研究了不同磁场环境下一维Heisenberg XXZ自旋链中两量子比特的热量子失协特性. 在四种不同的磁场环境下: 1) B1=B2=0 (无磁场); 2) B1≠0, B2=0 (磁场只作用于其中一个量子比特); 3) B1=B2 (均匀磁场); 4) B1=-B2 (非均匀磁场), 对分别作用在每个量子比特上的磁场B1和B2对其量子关联的影响作了详细的讨论, 且数值计算和比较了其量子失协和量子纠缠的异同. 结果显示: 在有限温度下, 量子失协相比于量子纠缠更普遍, 且非均匀磁场相比于均匀磁场对量子失协和量子纠缠更有用, 更有利于量子通讯和量子信息处理过程.
关键词:
量子关联
纠缠
量子失协 相似文献