共查询到20条相似文献,搜索用时 314 毫秒
1.
2.
研究了一般形式类GHZ(Greenberger-Horne-Zeilinger)态的共生纠缠度及非定域性, 给出了类GHZ纠缠态的共生纠缠、Mermin不等式和Svetlichny不等式的解析表达式, 并通过数值计算讨论纠缠与非定域性之间的关系. 结果表明, 类GHZ纠缠态的共生纠缠和两个Bell型不等式描述的非定域性是一致的, Bell算符及其参量, 能够明显展示量子态的非定域特性.
关键词:
量子信息
类GHZ态
共生纠缠
Bell型不等式 相似文献
3.
在非旋波近似下, 利用相干态正交化展开方法, 对两量子比特与谐振子相耦合系统中的量子纠缠演化特性进行了精确计算. 讨论了在共振时, 两量子比特和谐振子耦合系统基态的性质以及量子比特和谐振子之间的纠缠与量子比特-量子比特间的纠缠的不同. 结果表明: 当不考虑外场时, 量子比特-量子比特间的纠缠随着耦合强度的增大从1迅速地减小到零, 表明了量子比特-量子比特间的纠缠对耦合强度是非常敏感的; 而量子比特和谐振子之间的纠缠随着耦合强度的增大从零迅速地增大, 但不能达到理论上的最大值2; 当初始时刻两量子比特没有纠缠时, 在弱耦合强度下, 真空场不能导致纠缠的产生; 而强的耦合非旋波效应则可以导致纠缠的突然产生现象.
关键词:
相干态正交化展开
非旋波近似
量子纠缠 相似文献
4.
5.
本文利用绝热近似方法和精确对角化方法研究三量子比特Dicke模型中的纠缠动力学.处于两种典型的纠缠态GHZ态和W态上的量子比特在时间演化过程中与辐射光场发生强耦合作用,在各种子系统间产生纠缠,通过分析这些纠缠的演化特性发现初始GHZ态的三体纠缠鲁棒性比W态强,这与旋波近似结论一致.与旋波近似下结果不同的是,两种态中任意一对量子比特间的纠缠都随时间演化到几乎为零,而三体纠缠随时间周期演化,且纠缠程度相对较强,说明系统中的强耦合作用通过抑制量子比特中的对纠缠来支持三体纠缠. 相似文献
6.
提出一种把量子隐形传态、最佳普适量子比特翻转和最佳普适量子克隆三者结合起来的量子比特普适远程翻转和克隆方案.当发送者和处于不同地点的三个接收者共享一个特定的四粒子纠缠态作为量子信道时,通过发送者的Bell基测量、经典通信和各个接收者的局域幺正变换,一个接收者能够以2/3的最佳保真度得到一份原未知量子比特的正交补态,另外两个接收者能够分别以5/6的最佳保真度得到原未知量子比特的一份拷贝.此方案用较少的量子纠缠资源同时完成了未知量子比特的普适远程翻转和克隆,且其保真度分别达到了最佳.实现此方案的关键在于构造出发送者和接收者共享的特定四粒子纠缠态作为量子信道,分析了此特殊四粒子态内在的纠缠结构. 相似文献
7.
热库诱导的两比特量子纠缠与量子关联 总被引:1,自引:0,他引:1
对比研究了处于热库中的两量子比特的量子纠缠和量子关联随时间的演化。数值模拟的结果表明,尽管热库几乎总能诱导两量子比特的量子纠缠与量子关联,但二者的动力学演化并不完全相同。在与热库的相互作用中,两比特初始形成量子纠缠,随后纠缠逐渐消失,两比特形成纠缠以外的量子关联并得到维持。由此看出,相比于量子纠缠,量子关联对消相干的影响表现得更为稳健。 相似文献
8.
对非旋波近似下两量子比特与单模光场耦合系统进行了求解.在定态问题中精确计算了系统能谱与耦合强度g的关系,通过解析求解可以发现,系统能谱中总有一条能级始终为常数与耦合强度g无关.在动力学问题中,研究了初始时刻纠缠在Bell态的两个原子与单模真空态腔场耦合时量子纠缠的演化问题,讨论了纠缠的突然死亡现象.结果表明:量子纠缠的演化具有周期性,随着耦合强度g逐渐增大,纠缠周期T随之减小,第一次出现纠缠突然死亡的时间不断缩短;在耦合强度较小时,随着原子间偶极相互作用参数η的增大纠缠演化周期逐渐增加,并且不会出现纠缠突然死亡. 相似文献
9.
10.
近年来有研究发现量子失协可以度量非纠缠的量子关联,而且非纠缠的量子关联在量子通信和量子计算中起到很重要的作用.本文研究了磁场,两种三体相互作用,各向异性参数,耦合常数,温度等参数对同时具有两种三体相互作用海森堡XXZ自旋链系统的量子纠缠,几何失协的影响以及与量子相变的关系.研究表明:量子纠缠和几何失协都可以清晰的表征本模型系统的量子相变现象;随着XZX+YZY型三体相互作用的增加量子纠缠和几何失协即使在高温时也可达到最大值;几何失协比量子纠缠更全面地描述了量子关联;XZY-YZX型三体相互作用的增加对量子纠缠有抑制作用;XZY-YZX型三体相互作用在一定区域内的增加对几何失协有抑制作用,在另一区域的增加可使几何失协增大到一个稳定的非零值.增大磁场和自旋耦合常数,减小各向异性参数会使纠缠的临界温度变大;调节自旋耦合常数可更有效的使量子纠缠和几何失协在高温时仍有一个较大的值.同时发现,在磁场0B5和各向异性参数-1J_Z10的区域两种量子关联都可以维持在最大值. 相似文献
11.
We have studied the analytical Markovian and non-Markovian dynamics of quantum correlations, such as entanglement, quantum discord and Bell nonlocalities for three noisy qubits. Quantum correlation as measured by quantum discord is found to be immune to death contrary to entanglement and Bell nonlocality for initial GHZ- or W-type mixed states. 相似文献
12.
Ling-Yun Sun Li Xu Jing Wang Ming Li Shu-Qian Shen Lei Li Shao-Ming Fei 《Frontiers of Physics》2021,16(3):31501
Nonlocal quantum correlations among the quantum subsystems play essential roles in quantum science. The violation of the Svetlichny inequality provides sufficient conditions of genuine tripartite nonlocality. We provide tight upper bounds on the maximal quantum value of the Svetlichny operators under local filtering operations, and present a qualitative analytical analysis on the hidden genuine nonlocality for three-qubit systems. We investigate in detail two classes of three-qubit states whose hidden genuine nonlocalities can be revealed by local filtering. 相似文献
13.
The important applications of quantum dot system are to implement logic operations and achieve universal quantum computing based on different quantum nonlocalities. Here, we characterize the quantum steering, Bell nonlocality, and nonlocal advantage of quantum coherence (NAQC) of quantum dot system suffering nonunital and unital channels. The results reveal that quantum steering, Bell nonlocality, and NAQC can display the traits of dissipation, enhancement, and freezing. One can achieve the detections of quantum steering, Bell nonlocality, and NAQC of quantum dot system in different situations. Among these quantum nonlocalities, NAQC is the most fragile, and it is most easily influenced by different system parameters. Furthermore, considering quantum dot system coupling with amplitude damping channel and phase damping channel, these quantum nonlocalities degenerate with the enlargement of the channel parameters $t$ and $\varGamma$. Remarkably, measurement reversal can effectively control and enhance quantum steering, Bell nonlocality, and NAQC of quantum dot system suffering from decoherence, especially in the scenarios of the amplitude damping channel and strong operation strength. 相似文献
14.
Nonclassical correlations have been found useful in many quantum information processing tasks, and various measures have been proposed to quantify these correlations. In this work, we mainly study one of nonclassical correlations, called measurement-induced nonlocality (MIN). First, we establish a close connection between this nonlocal effect and the Bell nonlocality for two-qubit states. Then, we derive a tight monogamy relation of MIN for any pure three-qubit state and provide an alternative way to obtain similar monogamy relations for other nonclassical correlation measures, including squared negativity, quantum discord, and geometric quantum discord. Finally, we find that the tight monogamy relation of MIN is violated by some mixed three-qubit states, however, a weaker monogamy relation of MIN for mixed states and even multi-qubit states is still obtained. 相似文献
15.
Entanglement, quantum steering and Bell nonlocality can be used to describe the distinct quantum correlations of quantum systems. Because of their different characteristics and application fields, how to divide them quantitatively and accurately becomes particularly important. Based on the sufficient and necessary criterion for quantum steering of an arbitrary two-qubit T-state, we derive the inequality relations between quantum steering and entanglement as well as between quantum steering and Bell nonlocality for the T-state. Additionally, we have verified those relations experimentally. 相似文献
16.
Jing Ma Li-Nan Jiang Si-Yuan Yu Qi-Wen Ran Li-Ying Tan 《International Journal of Theoretical Physics》2014,53(11):3843-3855
We investigate the entanglement dynamics of the two-qubit entanglement quantum system when they transmitted through the Pauli channels and the depolarizing channel both independently or collectively. Making use of the concurrence we found that the entanglement of a kind of mixed two-qubit system defined in this paper can be preserved in the collective Pauli σ y noise channel, but the entanglement of the other kind of mixed two-qubit system can be preserved in the collective Pauli σ z noise channel. Meanwhile, our quantum systems will undergoing the entanglement sudden death (ESD) in collective depolarizing channel when they return to the maximally entangled Bell states. The reason is the Landblad operators in depolarizing channel are non-commuting operators and this finding is in accord with the previous study. 相似文献
17.
Modeling the qubit by a two-level semiclassical detector coupled to a massless scalar field, we investigate how the Unruh effect affects the nonlocality and entanglement of two-qubit and three-qubit states when one of the entangled qubits is accelerated. Two distinct differences with the results of free field model in non-inertial frames are (i) for the two-qubit state, the CHSH inequality cannot be violated for sufficiently large but finite acceleration, furthermore, the concurrence will experience “sudden death”; and (ii) for the three-qubit state, not only does the entanglement vanish in the infinite acceleration limit, but also the Svetlichny inequality cannot be violated in the case of large acceleration. 相似文献
18.
ZHAO Ming-Jing LI Zong-Guo LI Bo FEI Shao-Ming WANG Zhi-Xi LI-JOST Xian-Qing 《理论物理通讯》2011,56(2):253-257
We investigate the nonlocality of Schmidt-correlated (SC) states, and present analytical expressions of the maximum violation value of Bell inequalities. It is shown that the violation of Clauser-Horne-Shimony-Holt (CHSH) inequality is necessary and sufficient for the nonlocality of two-qubit SC states, whereas the violation of the Svetlichny inequality is only a sufficient condition for the genuine nonlocality of three-qubit SC states. Furthermore, the relations among the maximum violation values, concurrence, and relative entropy entanglement are discussed. 相似文献
19.
Guo-Feng Zhang Heng Fan Ai-Ling Ji Zhao-Tan Jiang Ahmad Abliz Wu-Ming Liu 《Annals of Physics》2011,326(10):2694-2701
Bell nonlocality, entanglement and nonclassical correlations are different aspects of quantum correlations for a given state. There are many methods to measure nonclassical correlations. In this paper, nonclassical correlations in two-qubit spin models are measured by the use of measurement-induced disturbance (MID) [S. Luo, Phys. Rev. A 77 (2008) 022301] and geometric measure of quantum discord (GQD) [B. Daki?, V. Vedral, C. Brukner, Phys. Rev. Lett. 105 (2010) 190502]. Their dependences on external magnetic field, spin–spin coupling, and the Dzyaloshinskii–Moriya (DM) interaction are presented in detail. We also compare Bell nonlocality, entanglement measured by concurrence, MID and GQD and illustrate their different characteristics. 相似文献
20.
量子关联是量子信息、量子计算与量子计量领域的重要资源, 在量子纠缠和贝尔非局域性中, 两子系统起着同等关键的作用, Einstein-Podolsky-Rosen (EPR)量子引导关联的强度介于量子纠缠和贝尔非局域性之间, 对单向EPR量子引导关联而言两子系统的作用不对等. 本文研究了双模Bose-Hubbard模型中模间量子关联的动态特性, 揭示了EPR量子引导关联的取向对系统初态模间交换对称性的依赖关系. 根据Hillery-Zubairy纠缠判据以及基于最大平均量子Fisher信息的纠缠判据考察了系统初态对模间量子纠缠演化规律的影响. 如果模间耦合强度远大于同一势阱内粒子间的相互作用, 初始处于SU(2)相干态的系统在具有确定的两子系统交换对称性的条件下, 其量子关联呈现简单的周期性演化规律; 当这种对称性破缺时, 模间量子关联的演化呈现较复杂的崩塌与回复现象. 相似文献