共查询到20条相似文献,搜索用时 15 毫秒
1.
Jiahua Wei Lei Shi Lihua Ma Yang Xue Xuchun Zhuang Qiaoyan Kang Xuesong Li 《Quantum Information Processing》2017,16(10):260
We propose a novel scheme for remote preparation of an arbitrary n-qubit state with the aid of an appropriate local \(2^n\times 2^n\) unitary operation and n maximally entangled two-qubit states. The analytical expression of local unitary operation, which is constructed in the form of iterative process, is presented for the preparation of n-qubit state in detail. We obtain the total successful probabilities of the scheme in the general and special cases, respectively. The feasibility of our scheme in preparing remotely multi-qubit states is explicitly demonstrated by theoretical studies and concrete examples, and our results show that the novel proposal could enlarge the applied range of remote state preparation. 相似文献
2.
Quantifying and understanding quantum correlations may give a direct reply for many issues regarding the interesting behaviors of quantum system. To explore the quantum correlations in quantum teleportation, we have used a two-qubit Heisenberg XYZ system with spin–orbit interaction as a quantum channel to teleport an unknown state. By using different measures and standard teleportation protocols, we have derived the analytical expressions for quantum discord, entanglement of formation, purity, and maximal teleportation fidelity of the system. We compare their different characteristics and analyze the relationships between these quantities. 相似文献
3.
Jiahua Wei Lei Shi Junwen Luo Yu Zhu Qiaoyan Kang Longqiang Yu Hao Wu Jun Jiang Boxin Zhao 《Quantum Information Processing》2018,17(6):141
In this paper, we present an efficient scheme for remote state preparation of arbitrary n-qubit states with real coefficients. Quantum channel is composed of n maximally two-qubit entangled states, and several appropriate mutually orthogonal bases including the real parameters of prepared states are delicately constructed without the introduction of auxiliary particles. It is noted that the successful probability is 100% by using our proposal under the condition that the parameters of prepared states are all real. Compared to general states, the probability of our protocol is improved at the cost of the information reduction in the transmitted state. 相似文献
4.
Jiahua Wei Lei Shi Yu Zhu Yang Xue Zhiyan Xu Jun Jiang 《Quantum Information Processing》2018,17(3):70
We propose an efficient scheme for remotely preparing an arbitrary n-qubit equatorial state via n two-qubit maximally entangled states. Compared to the former scheme (Wei et al. in Quantum Inf Process 16:260, 2017) that has the 50% successful probability when the amplitude factors of prepared states are \(2^{-n{/}2}\), the probability would be increased to 100% by using of our modified proposal. The feasibility of our scheme for remote preparation arbitrary multi-qubit equatorial states is explicitly demonstrated by theoretical studies and concrete examples. 相似文献
5.
Andreas F. Terzis Petros Androvitsaneas Emmanuel Paspalakis 《Quantum Information Processing》2012,11(6):1931-1950
We investigate the thermal quantum discord and classical correlations in a two-qubit Ising model interacting with a site-dependent external magnetic field. Systematic study of all correlations is performed for various values of the system??s temperature, and the magnetic field magnitude and direction on each site. Our results reveal interesting findings as regrowth regions of the classical and quantum correlations. Moreover unexpected bahavior as for example increase of the quantum correlations with the increase of the anisotropy of the applied magnetic fields for specific values of the external parameters is reported. By comparing our quantum discord data with the entanglement of formation, we have concluded that the major source of quantum correlations is the entanglement. Overall, we have found that the independent control of each spin site by external fields is a very practical and robust way of achieving significant quantum discord useful in quantum computation and information proccesses. 相似文献
6.
Quantum Information Processing - We consider the support of the limit distribution of the Grover walk on crystal lattices with the linear scaling. The orbit of the Grover walk is denoted by the... 相似文献
7.
Quantum Information Processing - We present a new scheme for quantum teleportation that one can teleport an unknown state via a non-maximally entangled channel with certainly, using an auxiliary... 相似文献
8.
We demonstrate a new method to achieve the maximum singlet fraction using an entangled mixed two-qubit state as a resource. For this, we establish a tight upper bound on singlet fraction and show that the maximal singlet fraction obtained in Verstraete and Verschelde (Phys Rev Lett 90:097901(1)–097901(4), 2003) does not attain the upper bound on the singlet fraction derived here. Interestingly, we found that the required upper bound can, in fact, be achieved using local filtering operations. 相似文献
9.
Quantum entanglement can offer a quadratic enhancement in the precision of parameter estimation. We here study the protection of quantum Fisher information (QFI) of the phase parameter in entangled-atom states within the framework of independently dissipative environments and driven individually by classical fields. It is shown that the QFI of the phase parameter can be protected effectively only when the classical fields that drive all atoms are suitably strong, and if one of them vanishes or is very weak, then the ability of protection loses, no matter how strong the other driving fields are. We also study the evolution of fidelity of the entangled state itself and find that though the protections of QFI and quantum states are two different notions, the method can also be used to protect quantum states effectively when the driving fields are suitably strong. 相似文献
10.
11.
A. I. Zenchuk 《Quantum Information Processing》2012,11(6):1551-1570
We introduce a measure of quantum correlations in the N-qubit quantum system which is invariant with respect to the SU(2 N ) group of transformations of this system. This measure is a modification of the quantum discord introduced earlier and is referred to as the unitary or SU(2 N )-invariant discord. Since the evolution of a quantum system is equivalent to the proper unitary transformation, the introduced measure is an integral of motion and is completely defined by eigenvalues of the density matrix. As far as the calculation of the unitary invariant discord is rather complicated computational problem, we propose its modification which may be found in a simpler way. The case N?=?2 is considered in details. In particular, it is shown that the modified SU(4)-invariant discord reaches the maximum value for a pure state. A geometric measure of the unitary invariant discord of an N-qubit state is introduced and a simple formula for this measure is derived, which allows one to consider this measure as a witness of quantum correlations. The relation of the unitary invariant discord with the quantum state transfer along the spin chain is considered. We also compare the modified SU(4)-invariant discord with the geometric measure of SU(4)-invariant discord of the two-qubit systems in the thermal equilibrium states governed by the different Hamiltonians. 相似文献
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13.
Using the axiomatic definition of the quantum coherence measure, such as the \(l_{1}\) norm and the relative entropy, we study the phenomena of two-qubit system quantum coherence through quantum channels where successive uses of the channels are memory. Different types of noisy channels with memory, such as amplitude damping, phase damping, and depolarizing channels effect on quantum coherence have been discussed in detail. The results show that quantum channels with memory can efficiently protect coherence from noisy channels. Particularly, as channels with perfect memory, quantum coherence is unaffected by the phase damping as well as depolarizing channels. Besides, we also investigate the cohering and decohering power of quantum channels with memory. 相似文献
14.
Zhiguo Qu Shengyao Wu Mingming Wang Le Sun Xiaojun Wang 《Quantum Information Processing》2017,16(12):306
As one of important research branches of quantum communication, deterministic remote state preparation (DRSP) plays a significant role in quantum network. Quantum noises are prevalent in quantum communication, and it can seriously affect the safety and reliability of quantum communication system. In this paper, we study the effect of quantum noise on deterministic remote state preparation of an arbitrary two-particle state via different quantum channels including the \(\chi \) state, Brown state and GHZ state. Firstly, the output states and fidelities of three DRSP algorithms via different quantum entangled channels in four noisy environments, including amplitude-damping, phase-damping, bit-flip and depolarizing noise, are presented, respectively. And then, the effects of noises on three kinds of preparation algorithms in the same noisy environment are discussed. In final, the theoretical analysis proves that the effect of noise in the process of quantum state preparation is only related to the noise type and the size of noise factor and independent of the different entangled quantum channels. Furthermore, another important conclusion is given that the effect of noise is also independent of how to distribute intermediate particles for implementing DRSP through quantum measurement during the concrete preparation process. These conclusions will be very helpful for improving the efficiency and safety of quantum communication in a noisy environment. 相似文献
15.
由于受物理资源和实验条件的限制,在经典计算机上对量子密钥分配(QKD)仿真,为研究者提供一种手段以便更好地掌握这类抽象协议。对以纠缠态为基础的E91协议的量子密钥分配过程进行仿真,重点对比分析了理想环境、有噪环境以及窃听环境下的仿真结果,并验证该量子密钥分配协议的安全性。 相似文献
16.
Paweł Caban Jakub Rembieliński Kordian A. Smoliński Zbigniew Walczak 《Quantum Information Processing》2017,16(7):178
We study selected aspects of non-classical correlations of arbitrary states from the stochastic local operations and classical communication orbit of rank-deficient two-qubit states. In particular, we find explicitly entanglement of formation and quantum discord for these states. Moreover, we determine and analyze the Einstein–Podolsky–Rosen steering ellipsoids corresponding to these states. 相似文献
17.
Prasenjit Deb 《Quantum Information Processing》2016,15(4):1629-1638
Quantum state space is endowed with a metric structure, and Riemannian monotone metric is an important geometric entity defined on such a metric space. Riemannian monotone metrics are very useful for information-theoretic and statistical considerations on the quantum state space. In this article, considering the quantum state space being spanned by \(2\times 2\) density matrices, we determine a particular Riemannian metric for a state \(\rho \) and show that if \(\rho \) gets entangled with another quantum state, the negativity of the generated entangled state is, upto a constant factor, equal to square root of that particular Riemannian metric . Our result clearly relates a geometric quantity to a measure of entanglement. Moreover, the result establishes the possibility of understanding quantum correlations through geometric approach. 相似文献
18.
By using the \(\chi \) -type entangled states, a novel scheme for multi-party quantum state sharing (MQSTS) of an arbitrary multi-qubit state is investigated. It is shown that the MQSTS scheme can be faithfully realized by performing appropriate Bell state measurements, Z basis measurements and local unitary operations, rather than multi-qubit entanglement or multi-particle joint measurements. Thus, our MQSTS scheme is more convenient in a practical application than some previous schemes. Furthermore, its intrinsic efficiency for qubits approaches 100 %, and the total efficiency really approaches the maximal value, which is higher than those of the previous MQSTS schemes. Finally, we analyze the security from the views of participant attack and outside attack in detail. 相似文献
19.
Quantum correlations characterized by quantum entanglement and quantum discord play important roles in many quantum information processing. We study the relations among the entanglement of formation, concurrence, tangle, linear entropy-based classical correlation and von Neumann entropy-based classical correlation . We present analytical formulae of linear entropy-based classical correlation for arbitrary \(d\otimes 2\) quantum states and von Neumann entropy-based classical correlation for arbitrary \(2\otimes 2\) rank-2 quantum states. From the von Neumann entropy-based classical correlation, we derive an explicit formula of quantum discord for arbitrary rank-2 two-qubit quantum states. 相似文献