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The effects of spin-spin interaction on thermed entanglement of a two-qubit Heisenberg XYZ model with different inhomogeneous magnetic fields are investigated. It is shown that the entanglement is dependent on the spin-spin interaction and the inhomogeneous magnetic fields. The larger the Ji (i-axis spin-spin interaction), the higher critical value the Bi (i-axis uniform magnetic field) has. Moreover, in the weak-field regime, the larger Ji corresponds to more entanglement, while in the strong-field regime, different Ji correspond to the same entanglement. In addition, it is found that with the increase of Ji, the concurrence can approach the maximum value more rapidly for the smaller Bi, and can reach a larger value for the smaller bi (i-axis nonuniform magnetic field). So we can get more entanglement by increasing the spin-spin interaction Ji, or by decreasing the uniform magnetic field Bi and the nonuniform magnetic field hi. 相似文献
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We propose a scheme to implement an unconventional geometric phase gate in circuit QED, i.e. two superconducting charge qubits inside a superconducting transmission line resonator. The quantum operation depends only on global geometric features, and thus is insensitive to the state of the cavity mode. 相似文献
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采用时间演化算符方法,研究-型三能级原子与双模腔场共振相互作用的辐射谱,尤其在真空场中拉比(Rabi)分裂.给出了辐射谱一般公式。并讨论在粒子数纯态光场激励下的辐射频谱结构。结果表明:一般辐射谱呈对称的12蜂结构. 相似文献
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运用全量子理论并结合数值计算方法,研究了处于Bell态的两个全同二能级纠缠原子与双模纠缠相干光场相互作用系统的光子统计性质.分析了双原子体系的初态、光场的平均光子数、双模纠缠相干光场的纠缠程度以及双原子体系的原子间耦合强度对双模光场的光子统计性质的影响.结果表明:双原子体系的初态为|β00〉、|β10〉时,光场在其演化过程中不出现光子的反聚束效应;而当原子初态为|β01〉或|β11〉时,在一定的条件下可出现光子的反聚束效应.并且在光场的演化过程中,光子的反聚束效应出现的次数、时间和深度极其敏感地依赖于初始光场的平均光子数,而受到双模纠缠光场的纠缠程度以及双原子间偶极作用强度的影响很微弱. 相似文献
15.
This paper proposes a scheme for entanglement concentration of unknown triparticle W class states with a certain probability. This protocol is mainly based on the coincidences of single-photon detectors and requires single-photon detectors and linear optical elements. The scheme is feasible within current technology. 相似文献
16.
This paper proposes an experimentally feasible scheme for
teleportation of an unknown two-atom entangled state, where a
cluster state is used as the quantum channel. This scheme does not
need any joint measurement. In addition, the successful probability
and fidelity of teleportation can both reach 1.0. The current scheme
can be realized within the current experimental technology. 相似文献
17.
The pre-and post-selection processes of the "two-state vector formalism" lead to a fair sampling loophole in Bell test, so it can be used to simulate post-quantum correlations. In this paper, we propose a physical implementation of such a correlation with the help of quantum non-demolition measurement, which is realized via the cross-Kerr nonlinear interaction between the signal photon and a probe coherent beam. The indirect measurement on the polarization state of photon is realized by the direct measurement on the phase shift of the probe coherent beam, which enhances the detection efficiency greatly and leaves the signal photon unabsorbed. The maximal violation of the CHSH inequality 4 can be achieved by pre-and post-selecting maximally entangled states. The reason why we can get the post-quantum correlation is that the selection of the results after measurement opens fair-sampling loophole. The fair-sampling loophole opened here is different from the one usually used in the currently existing simulation schemes for post-quantum correlations,which are simulated by selecting the states to be measured or enlarging the Hilbert space. So, our results present an alternative way to mimic post-quantum correlations. 相似文献
18.
Nearly Deterministic Teleportation of a Photonic Qubit with Weak Cross-Kerr Nonlinearities 下载免费PDF全文
Scheme for teleporting an unknown single-qubit photonic state is revisited. With the help of quantum nondemolition measurements, the scheme now can be achieved in an almost deterministic way. The weak-cross-Kerr-nonlinearities-based quantum nondemolition measurement acts as an entangler as well as the Bell-state analyzer, and thus plays a similar role as the CNOT gate in the teleportation process. This improvement makes the present scheme more efficient than the schemes using nonunitary projective measurements and feasible with the current experimental technology. 相似文献
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