共查询到20条相似文献,搜索用时 15 毫秒
1.
We evaluate the monogamy inequality for symmetric, non-symmetric pure states of importance in terms of squared concurrence, squared entanglement of formation, squared negativity of partial transpose and compare the corresponding tangles. We show that though concurrence and concurrence tangle are zero for two special classes of mixed entangled states, both negativity tangle and entanglement of formation(EOF) tangle turn out to be non-zero. A comparison of different tangles is carried out in each case and it is shown that while the concurrence tangle captures the genuine multiqubit entanglement in N-qubit pure states with N distinct spinors(containing GHZ and superposition of W-, obverse W states)either negativity tangle or EOF tangle is to be used as a better measure of entanglement in the W-class of states with two distinct spinors and in the special classes of mixed multiqubit states. 相似文献
2.
Preparation of entangled squeezed states and quantification of their entanglement 总被引:3,自引:0,他引:3 下载免费PDF全文
We propose a scheme for generating bipartite and multipartite entangled squeezed states via the Jaynes-Cummings model with large detuning. Bipartite entanglement of these entangled states is quantified by the concurrence. We also use the N-tangle to compute multipartite entanglement of these multipartite entangled squeezed states. Finally we discuss two limiting cases which arise from r→∞ and r→0, in which the multipartite entangled squeezed state reduces correspondingly into an N-qubit Greenberger-Horne-Zeilinger state and an N-qubit W state. 相似文献
3.
We present an interesting monogamy equation for (2⊗2⊗n)-dimensional pure states, by which a quantity is found to characterize the tripartite entanglement with the GHZ type and W type entanglements as a whole. In particular, we, for the first time, reveals that for any quantum state of a pair of qubits, the difference between the two remarkable entanglement measures, concurrence and negativity, characterizes the W type entanglement of tripartite pure states with the two-qubit state as reduced density. 相似文献
4.
Based on the Wu's scheme [C.F. Wu, J.L. Chen, L.C. Kwekl, and C.H. Ohel, Phys. Rev. A 73 (2006) 012310], we prepare the general N-qubit W state. We find that the concurrence of two qubits in general N-qubit W state is only related to their coefficients and we successfully apply the general N-qubit W state to quantum state transfer and quantum state prepare like that in two-qubit system. 相似文献
5.
Based on the Wu's scheme [C.F. Wu, J.L. Chen, L.C. Kwekl, and C.H. Ohel, Phys. Rev. A 73 (2006) 012310], we prepare the general N-qubit W state. We find that the concurrence of two qubits
in general N-qubit W state is only related to their coefficients and we successfully apply the general N-qubit
W state to quantum state transfer and quantum state prepare like that in two-qubit system. 相似文献
6.
We show that higher order intergroup covariances involving even number of qubits are necessarily positive semidefinite for N-qubit separable states, which are completely symmetric under permutations of the qubits. This identification leads to a family of sufficient conditions of inseparability based on the negativity of 2kth order intergroup covariance matrices (2k=N) of symmetric N-qubit systems. These conditions have a simple structure and detect entanglement in all even partitions of the symmetric multiqubit system. The observables involved are feasible experimental quantities and do not demand full state determination through quantum state tomography. 相似文献
7.
Rasim Dermez 《Journal of Russian Laser Research》2017,38(5):408-415
We investigate entangled states of an atomic trapped ion interacting with two phonons in the Λ configuration forming a twelve-dimensional Hilbert space. We study two elaborated measures, namely, the concurrence C and negativity N, which are important in current theoretical studies. Therefore, we work with the three-dimensional reduced density matrix in calculating the measures elaborated for pure qudit states in the ionic–phononic system. To demonstrate the benefits of the family of the two measures elaborated, we perform the calculations for different values of the Lamb–Dicke (LD) parameter η = 0.01, 0.3, and 0.5. Finally, we show that the pure qudit states under study are maximum entangled states. 相似文献
8.
Multi-mode entangled coherent states are important resources for linear optics quantum computation and teleportation. Here we introduce the generalized balanced N-mode coherent states which recast in the multi-qudit case. The necessary and sufficient condition for bi-separability of such balanced N-mode coherent states is found. We particularly focus on pure and mixed multi-qubit and multi-qutrit like states and examine the degree of bipartite as well as tripartite entanglement using the concurrence measure. Unlike the N-qubit case, it is shown that there are qutrit states violating monogamy inequality. Using parity, displacement operator and beam splitters, we will propose a scheme for generating balanced N-mode entangled coherent states for even number of terms in superposition. 相似文献
9.
We show that although we cannot distil a singlet from many pairs of bound entangled states, the concurrence and the tangle of two entangled quantum states are always strictly larger than those of one of them, even both entangled quantum states are bound entangled. We present a relation between the concurrence and the fidelity of optimal teleportation. We also give new upper and lower bounds for concurrence and tangle. 相似文献
10.
11.
This paper presents monogamy relations for three-qubit quantum states by using convex-roof extended negativity, which inspires studying the difference between the three entanglement measures, concurrence, negativity and convexroof extended negativity. It finds that the convex-roof extended negativity is a stronger entanglement measure than concurrence in multipartite higher-dimensional quantum system. 相似文献
12.
Persistent entanglement in arrays of interacting particles 总被引:18,自引:0,他引:18
We study the entanglement properties of a class of N-qubit quantum states that are generated in arrays of qubits with an Ising-type interaction. These states contain a large amount of entanglement as given by their Schmidt measure. They also have a high persistency of entanglement which means that approximately N/2 qubits have to be measured to disentangle the state. These states can be regarded as an entanglement resource since one can generate a family of other multiparticle entangled states such as the generalized Greenberger-Horne-Zeilinger states of 相似文献
13.
ZHAO Hui WANG Zhi-Xi 《理论物理通讯》2007,47(1):45-48
We investigate the entanglement of formation for a class of high-dimensional quantum mixed states. We present a kind of generalized concurrence for a class of high-dimensional quantum pure states such that the entanglement of formation is a monotonically increasing convex function of the generallzed concurrence, from the monotonicity and convexity the entanglement of formafion for a class of high-dimensional mixed states has been calculated analytically, 相似文献
14.
K. Nagata 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(3):441-444
The theoretical resource state for the implementation of the Deutsch-Jozsa algorithm is a multiqubit pure uncorrelated state.
We show that N-qubit pure uncorrelated quantum states cannot admit rotationally invariant nonlocal realistic theories with
a violation factor of 3N. We find
the violation factor 3Nwhen the measurement setup is entire range of settings for each of the observers, that is, considering rotationally invariant
nonlocal realistic theories along with the property of a correlation function in the quantum theory. The implementation of
the Deutsch-Jozsa algorithm theoretically relying on N-qubit pure uncorrelated states rules out rotationally invariant nonlocal
realism with a violation factor of 3Nin an ideal case. Our analysis relies on the property of theoretical resource states for the algorithm. We cannot simulate
the Deutsch-Jozsa algorithm by using rotationally invariant nonlocal realistic theories due to the property of theoretical
resource states for the algorithm. 相似文献
15.
MUZAFFAR QADIR LONE 《Pramana》2016,87(1):16
We investigate the dynamics of entanglement given by the concurrence of a two-qubit system in the non-Markovian setting. A quantum master equation is derived, which is solved in the eigenbasis of the system Hamiltonian for X-type initial states. A closed formula for time evolution of concurrence is presented for a pure state. It is shown that under the influence of dissipation non-zero entanglement is created in unentangled two-qubit states which decay in the same way as pure entangled states. We also show that under real circumstances, the decay rate of concurrence is strongly modified by the non-Markovianity of the evolution. 相似文献
16.
We analyze the atomic Wehrl entropy and negativity as compared with concurrence for qudit pure states in a trapped ion. We
use the density matrix in calculating the three measures of quantum correlations. We find that a long surviving entangled
qudit can be established between the three atomic levels and vibrational modes. We observe three distinct entanglements in
response to an increasing Lamb–Dicke parameter. 相似文献
17.
Multi-qubit pure states play an important role in the application of quantum entanglement. In this paper, we find that the maximally multi-qubit pure states have a simple recurrence relation. The existence recurrence relation of multi-qubit maximally pure states of N-qubit for N = 2,3,⋯ ,8 are demonstrated. Further, some new characterizations of the multipartite maximally entangled states are found with the recurrence relation. These results may open a new window for constructing maximally multi-qubit states.
相似文献18.
本文应用negativity和concurrence两种纠缠度量标准,考察了双原子与双模光场相互作用系统中,原子间纠缠和光场模间纠缠随时间的演化规律,发现它们在时间演化过程中可以相互转换,在一定条件下两者具有很好的对应关系;对于两量子位系统,negativity和concurrence的取值范围一样,在判断纠缠存在与否的标准上也完全相同,但当系统处于混态时二者的大小不能始终保持一致.
关键词:
量子纠缠
negetivity
concurrence
双原子
双模光场 相似文献
19.
20.
We generalize the Schmidt-correlated states to multipartite systems. The related equivalence under SLOCC, the separability, entanglement witness, entanglement measures of negativity, concurrence and relative entropy are investigated in detail for the generalized Schmidt-correlated states. 相似文献