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The effects of amplitude damping in quantum noise channels on average fidelity of quantum teleportation are analyzed in Bloch sphere representation for every stage of teleportation. When the quantum channels are varied from maximally entangled states tonon-maximally entangled states, it is found that the effects of noise channels on the fidelity are nearly equivalent to each other for strong quantum noise. The degree of damage on the fidelity of non-maximally entangled channels is smaller than that of maximally entangled channels. The average fidelity of values larger than2/3 may be one representation indirectly showing how much theunavoidable quantum noise is. 相似文献
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The quantum teleportation with the entangled thermal state is investigated based on the completely anisotropic Heisenberg chain in the presence of the externally inhomogeneous magnetic field. The effects of the anisotropy and magnetic field for the quantum fidelity are studied in detail. The zero temperature limit and the features of the nonzero temperature for this nonclassical fidelity are obt8ained. We find that the quantum teleportation demands more stringent conditions than the thermal entanglement of the resource by investigating the threshold temperature of the thermal concurrence and the critical temperature of the maximal teleportation fidelity. The useful quantum teleportation should avoid the point of the phase transition of the system and the anisotropy of the chain and the external magnetic field can control the applicability of the resource in the quantum teleportation. 相似文献
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We examine entanglement teleportation,characterized by average fidelity,of two-qubit XY Z spin chain under different nonuniform magnetic field.The entanglement teleportation and the fidelity of entanglement teleportation are investigated separately.We show explicitly that the fidelity of entanglement teleportation can be enhanced by changing the direction of the magnetic field.This means that we can always get optimal fidelity by choosing the directions of magnetic field in the process of quantum teleportation.Moreover,the results show that in some cases the ferromagnetic chain also is a qualified candidate in the process of teleportation protocol. 相似文献
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双模最小关联混合态作为量子信道实现量子隐形传态的保真度 总被引：5，自引：0，他引：5
基于Braunstein和Kimble提出的B-K方案以双模最小关联混合态作为量子信道实施对未知量子态的隐形传送,并以传送相干态为例进行了研究.结果表明：双模最小关联混合态作为一种广义的Einstein-Podolsky-Rosen型纠缠态在实现量子隐形传态中能很好地担当量子信道的角色,在纠缠度和压缩度选择适当的条件下被传送未知量子态的保真度可以达到1.这是比双模压缩真空态更优越的量子信道.关键词：量子隐形传态双模最小关联混合态保真度 相似文献
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The dependence of fidelity on the squeezing parameter in teleportation of the squeezed coherent states 
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下载免费PDF全文 This paper investigates an analytical expression of teleportation fidelity in the teleportation scheme of a single mode of electromagnetic field.The fidelity between the original squeezed coherent state and the teleported one is expressed in terms of the squeezing parameter r and the quantum channel parameter(two-mode squeezed state) p.The results of analysis show that the fidelity increases with the increase of the quantum channel parameter p,while the fidelity decreases with the increase of the squeezing parameter r of the squeezed state.Thus the coherent state(r = 0) is the best quantum signal for continuous variable quantum teleportation once the quantum channel is built. 相似文献
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This paper investigates an analytical expression of teleportation fidelity in the teleportation scheme of a single mode of electromagnetic field. The fidelity between the original squeezed coherent state and the teleported one is expressed in terms of the squeezing parameter r and the quantum channel parameter (two-mode squeezed state) p. The results of analysis show that the fidelity increases with the increase of the quantum channel parameter p, while the fidelity decreases with the increase of the squeezing parameter r of the squeezed state. Thus the coherent state (r=0) is the best quantum signal for continuous variable quantum teleportation once the quantum channel is built. 相似文献
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本文提出了一个方案:将三粒子纠缠态从一个发送者传给两个接收者之一,并将其推广到N粒子纠缠态的传送。这里,我们仅用两粒子纠缠对作通道就实现了N粒子纠缠态的传送。此方案相比以往的方案节省了大量纠缠资源,且成功传送的几率达到了1。 相似文献
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Two protocols for transmitting an unknown single-photon state and an unknown non-maximally entangled EPR state are presented by using the quantum channel of three-phonton GHZ （Greenberger-Horne-Zeilinger） state, which can be realized with unitary success probability when collective noise is taken into account. The protocols can also be generalized to transmit multi-photon state or to realize quantum communication in collective noise channel. 相似文献
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Xiao-Fang Liu 《中国物理 B》2022,31(5):50301-050301
Quantum controlled teleportation is the transmission of the quantum state under the supervision of a third party. This paper presents the theoretical and experimental results of an arbitrary two-qubit quantum controlled teleportation scheme, in which the sender Alice only needs to perform two Bell state measurements and the receiver Bob can perform an appropriate unitary operation to reconstruct the arbitrary two-qubit states under the control of the supervisor Charlie. The operation process of the scheme is verified on the IBM quantum experience platform, and the accuracy of the transmitted quantum state is further checked by performing quantum state tomography. Meanwhile, a good fidelity is obtained by using the theoretical density matrix and the experimental density matrix. A sequence of photonic states is introduced to analyze the possible intercept-replace-resend, intercept-measure-resend, and entanglement-measure-resend attacks on this scheme. The results proved that our scheme is highly secure. 相似文献
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基于Braunstein与Kimble的连续变量量子隐形传态方案,通过调节输出端位移因子可以优化单模压缩相干态和单模压缩真空态量子隐形传态的保真度;分析了单模压缩态的压缩参数对保真度的影响。 相似文献
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In the paper, taking the atomic EPR entanglement states as quantum channel, we investigate the fidelity of quantum teleportation of atomic state in thermal environment and vacuum reservoir by means of quantum theory of damping-density operator approach, and the average fidelities are calculated. the resultsshow that the atomic quantum channel state |ø> = (1/21/2)(| 00>+ |11>) is more robust than | Φ> = (1/21/2)(|01> + |10>) in teleportation process when they are subject to the dissipative environments. 相似文献
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NI Hui-Ying FANG Jian-Xing ZHU Shi-Qun SHA Jin-Qiao JIANG Wei-Xing 《理论物理通讯》2008,49(2):333-337
In this paper we study the entanglement in a two-qubit spin in the XYZ model, and teleport a two-qubit entangled state using this spin chain in the condition of the thermal equilibrium as a quantum channel. We investigate the effects of the interaction of z-component Jz, the inhomogeneous magnetic field b, the anisotropy γ and the temperature T on the entanglement and fidelity. In order to characterize the quality of the teleported state, we research the average fidelity Fα. High average fidelity of the teleportation is obtained when the temperature is very low. Under some condition, we also find that when innomogeneity increases to a certain value, the average fidelity can exhibit a larger revival than that for less values of b. 相似文献
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基于Braunstein和Kimble方案以双模压缩真空态作为量子信道实施对单模最小关联混态量子隐性传态的可行性进行了研究.我们发现,单模最小关联混态在一定参数范围内呈现出压缩效应这种非经典性质,利用双模压缩真空态作为量子通道可以高保真的传递没有压缩效应的单模最小关联混态,但对呈现压缩效应的单模最小关联混态进行量子隐性传送时得到输出态的保真度较低.而且发现通过调节输出端位移因子的方法不能实现对单模最小关联混态保真度的优化. 相似文献
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This paper has investigated quantum teleportation of even and odd coherent states interms of the EPR entanglement states for continuous variables. It discusses therelationship between the fidelity and the entanglement of EPR states, which ischaracterized by the degree of squeezing and the gain of classical channels. Itshows that the quality of teleporting quantum states also depends on thecharacteristics of the states themselves. The properties of teleporting even and oddcoherent states at different intensities are investigated. The difference ofteleporting two such kinds of quantum states are analysed based on the quantumdistance function. 相似文献
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This paper investigates the thermal pairwise entanglement of athree-qubit Heisenberg XXZ chain in the presence of theDzyaloshinski--Moriya (DM) anisotropic antisymmetric interaction andquantum teleportation when using the Heisenberg chain as a channel.The entanglement dependences on the DM interaction and temperatureare given in detail. It obtains the relation between the concurrenceand average fidelity, and shows that the same concurrence can leaddifferent average fidelities. Moreover, it finds the thermallyentangled states which do not violate the Bell inequalities, and canstill be used for quantum teleportation. 相似文献
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在振幅阻尼信道上进行量子隐形传态的过程中, 量子Bell纠缠态将发生退相干, 导致隐形传态质量下降甚至通信失败. 为克服该影响, 本文提出了一种Bell纠缠态补偿方法. 在估计振幅阻尼信道参数的基础上, 将对纠缠态的补偿分为纠缠退相干发生之前的预补偿以及 经历量子振幅阻尼信道之后的匹配补偿两部分. 前者在纠缠源处进行, 后者在两个量子通信 用户处进行, 预补偿及匹配补偿参数与信道特性参数相关. 纠缠补偿完成后, 再进行隐形传态. 理论推导与性能分析结果表明, 相比于不进行纠缠补偿及仅在发生退相干之后进行的纠缠补偿, 本方法能够获得更高的隐形传态保真度, 适当调整补偿参数, 可使保真度接近于1, 对克服纠缠 退相干带来的隐形传态质量下降问题具有一定的意义. 相似文献
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Two protocols for transmitting an unknown single-photon state and anunknown non-maximally entangled EPR state are presented by using thequantum channel of three-phonton GHZ (Greenberger-Horne-Zeilinger)state, which can be realized with unitary success probability whencollective noise is taken into account. The protocols can also begeneralized to transmit multi-photon state or to realize quantumcommunication in collective noise channel. 相似文献