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We study maximally entangled states and fully entangled fraction in general d'\otimes d (d'\geq d) systems. Necessary and sufficient conditions for maximally entangled pure and mixed states are presented. As a natural generalization of the…

Quantum Physics · Physics 2016-10-27 Ming-Jing Zhao

Separability problem, to decide whether a given state is entangled or not, is a fundamental problem in quantum information theory. We propose a powerful and computationally simple separability criterion, which allows us to detect the…

Quantum Physics · Physics 2009-11-13 Cheng-Jie Zhang , Yong-Sheng Zhang , Shun Zhang , Guang-Can Guo

In quantum information theory, the reliable and effective detection of entanglement is of paramount importance. However, given an unknown state, assessing its entanglement is a challenging task. To attack this problem, we investigate the…

Quantum Physics · Physics 2015-12-09 Jochen Szangolies , Hermann Kampermann , Dagmar Bruß

We demonstrate how to efficiently derive a broad class of inequalities for entanglement detection in multi-mode continuous variable systems. The separability conditions are established from partial transposition (PT) in combination with…

Quantum Physics · Physics 2015-05-13 Qingqing Sun , Hyunchul Nha , M. Suhail Zubairy

This short note describes a method to tackle the (bipartite) quantum separability problem. The method can be used for solving the separability problem in an experimental setting as well as in the purely mathematical setting. The idea is to…

Quantum Physics · Physics 2007-05-23 L. M. Ioannou , B. C. Travaglione

The detection of multipartite entanglement in arbitrary dimensional systems is investigated. We derive useful $k$-separability criteria of mixed $n$-partite ($n\geq 3$) quantum states to detect $k$-nonseparable $n$-partite quantum states.…

Quantum Physics · Physics 2013-01-17 Ting Gao , Yan Hong

We introduce a set of Bell inequalities for a three-qubit system. Each inequality within this set is violated by all generalized GHZ states. More entangled a generalized GHZ state is, more will be the violation. This establishes a relation…

Quantum Physics · Physics 2017-11-02 Arpan Das , Chandan Datta , Pankaj Agrawal

I derive separability inequalities for Bell correlations of observables in arbitrary pure or mixed $N$ Qudit states in $D^N$-dimensional state space. I find states (a continuum of states if $D>3$) including maximally entangled states which…

Quantum Physics · Physics 2020-02-03 S. M. Roy

We consider entanglement detection for quantum key distribution systems that use two signal states and continuous variable measurements. This problem can be formulated as a separability problem in a qubit-mode system. To verify…

Quantum Physics · Physics 2007-05-23 Johannes Rigas , Otfried Gühne , Norbert Lütkenhaus

We review the criteria for separability and quantum entanglement, both in a bipartite as well as a multipartite setting. We discuss Bell inequalities, entanglement witnesses, entropic inequalities, bound entanglement and several features of…

Quantum Physics · Physics 2007-05-23 Barbara M. Terhal

Quantum entanglement and its paradoxical properties hold the key to an information processing revolution. Much attention has focused recently on the challenging problem of characterizing entanglement. Entanglement for a two qubit system is…

Quantum Physics · Physics 2009-11-07 Vivien M Kendon , Kae Nemoto , William J Munro

The relation between the violation of the Bell-CHSH inequalities and entanglement properties of quantum states is not clear so one may consider the mixedness of the system to understand the entanglement properties better than the Bell-CHSH…

Quantum Physics · Physics 2009-06-11 Satyabrata Adhikari

The experimental detection of quantum entanglement is of great importance in quantum information processing. We present two separability criteria based on the generalized realignment moments. By incorporating additional parameters, these…

Quantum Physics · Physics 2026-02-25 Xiaofen Huang , Xishun Zhu , Bin Chen , Naihuan Jing , Shao-Ming Fei

We discuss the problem of determining whether the state of several quantum mechanical subsystems is entangled. As in previous work on two subsystems we introduce a procedure for checking separability that is based on finding state…

Quantum Physics · Physics 2007-05-23 Andrew C. Doherty , Pablo A. Parrilo , Federico M. Spedalieri

We study the entanglement detection by using mutually unbiased measurements and provide a quantum separability criterion that can be experimentally implemented for arbitrary $d$-dimensional bipartite systems. We show that this criterion is…

Quantum Physics · Physics 2015-06-22 Bin Chen , Teng Ma , Shao-Ming Fei

We propose a scheme to evaluate the amount of quantum discord and entanglement of formation for mixed states, and reveal their ordering relation via an intrinsic relationship between the two quantities distributed in different partners of…

Quantum Physics · Physics 2015-05-19 Li-Xiang Cen , Xin-Qi Li , JiuShu Shao , YiJing Yan

Quantum states are represented by positive semidefinite Hermitian operators with unit trace, known as density matrices. An important subset of quantum states is that of separable states, the complement of which is the subset of…

Mathematical Physics · Physics 2020-12-04 Grigoriy Blekherman , H. M. Bharath

We study generalized concurrences as a tool to detect the entanglement of bipartite quantum systems. By considering the case of 2 X 4 states of rank 2, we prove that generalized concurrences do not, in general, give a necessary and…

Quantum Physics · Physics 2008-07-23 Laura Cattaneo , Domenico D'Alessandro

We study separability problem using general symmetric informationally complete measurements and propose separability criteria in $\mathbb{C}^{d_{1}}\otimes\mathbb{C}^{d_{2}}$ and…

Quantum Physics · Physics 2019-03-19 Ya Xi , Zhu-Jun Zheng , Chuan-Jie Zhu

Loopholes present in an experimental set-up can significantly affect the reliability of entanglement detection. We discuss two methods for detection of entanglement: one is by using the positive partial transposition criterion after quantum…

Quantum Physics · Physics 2023-05-02 Paranjoy Chaki , Kornikar Sen , Ujjwal Sen