Quantum entanglement of the binomial field interacting with a cascade three-level atom beyond the rotating wave approximation

Xue-Zao, Ren; Hong-Lu, Cong; Wang, XuWen; Xia, Jianping

doi:10.1007/s11433-011-4449-z

Cited by 4 publications

(2 citation statements)

References 28 publications

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“…One of the most fundamental problem in entanglement theory is to determine whether a given quantum state is entangled or not. Nowadays, a number of different entanglement criteria have been found [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

An entanglement criterion for states in infinite-dimensional multipartite quantum systems

2012

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In (Phys Lett A, 2002, 297: 4-8) an entanglement criterion for finite-dimensional bipartite systems is proposed: If ρ AB is a separable state, then Tr(ρ 2 A ) Tr(ρ 2 ) and Tr(ρ 2 B ) Tr(ρ 2 ). In the present paper this criterion is extended to infinite-dimensional bipartite and multipartite systems. The reduction criterion presented in (Phys Rev A, 1999, 59: 4206-4216) is also generalized to infinitedimensional case. Then it is shown that the former criterion is weaker than the later one. quantum state, entanglement criterion, infinite-dimensional system Citation: Wang Y Z, Hou J C, Guo Y. An entanglement criterion for states in infinite-dimensional multipartite quantum systems.

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Section: Introductionmentioning

confidence: 99%

An entanglement criterion for states in infinite-dimensional multipartite quantum systems

2012

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“…Quantum entanglement led to the experimental verification for Bell inequality which confirmed quantum mechanics [3]. In recent years, quantum entanglement has been one of the key driving forces that advanced the explosive development of quantum information and quantum computation [4][5][6][7][8][9][10][11][12]. Entanglement has developed from a philosophical concept into a frontier research paradigm, and much more attention has been paid to the quantification of entanglement.…”

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confidence: 99%

Entanglement of linear cluster states in terms of averaged entropies

Cao

Long

2013

Chin. Sci. Bull.

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An entanglement measure, multiple entropy measures (MEMS) was proposed recently by using the geometric mean of partial entropies over all possible i-body combinations of the quantum system. In this work, we study the average subsystem von Neumann entropies of the linear cluster state and investigated the quantum entanglement of linear cluster states in terms of MEMS. Explicit results with specific particle numbers are calculated, and some analytical results are given for systems with arbitrary particle numbers. Compared with other example quantum states such as the GHZ states and W states, the linear cluster states are "more entangled" in terms of MEMS, namely their averaged entropies are larger than the GHZ states and W states. Entanglement [1, 2] is one of the most salient properties of quantum systems. Quantum entanglement led to the experimental verification for Bell inequality which confirmed quantum mechanics [3]. In recent years, quantum entanglement has been one of the key driving forces that advanced the explosive development of quantum information and quantum computation [4][5][6][7][8][9][10][11][12]. Entanglement has developed from a philosophical concept into a frontier research paradigm, and much more attention has been paid to the quantification of entanglement. Two measures of entanglement, formation and distillation [15,16] were also studied and recognized as "good" entanglement measures.In studying quantum entanglement, the density matrices are often used. It should be mentioned that density matrix can represent different physical quantities. In the case of proper mixture, the density matrix represents the averaged "state" of an ensemble of "molecules", while the improper mixture describes the averaged "state" of a subsystem in a coupled quantum system. Though the mathematical expressions are the same, their physical properties are quite differ-*Corresponding author (email: gllong@mail.tsinghua.edu.cn) ent [49,50]. In studying quantum entanglement, we are actually using the improper mixture meaning of the density matrix. The reduced density matrix is obtained by tracing out other degrees of freedom of a composite quantum system. Based on separating the correlations encoded by a density matrix into a common set of marginals, Partovi [37] proposed a measurement in which N!/2 quantities are used to quantify an N-qubit system. In the case of N 3, a "good" measurement [38] can be constructed from the arithmetic average entropy of single reduced density matrices. Realizing the lack of one-qubit reduction, Higuchi et al. [51,52] proposed using the arithmetic mean of two-particle entropies as a measure of entanglement, and reported on a four-qubit entangled state:which is more entangled than the four-qubit GHZ state.

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