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Related papers: On Concurrence and Entanglement of Rank Two Channe…

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Quantification of quantum entanglement plays a crucial role in the study of quantum information tasks. We present analytical lower bounds for both concurrence and 2-concurrence based on the correlation matrices of bipartite quantum states.…

Quantum Physics · Physics 2025-03-21 Zhi-Bo Chen , Shao-Ming Fei

We study the entanglement of unitary operators on $d_1\times d_2$ quantum systems. This quantity is closely related to the entangling power of the associated quantum evolutions. The entanglement of a class of unitary operators is quantified…

Quantum Physics · Physics 2009-11-07 X. Wang , P. Zanardi

We give a representation for entanglement-breaking channels in separable Hilbert space that generalizes the "Kraus decomposition with rank one operators" and use it to describe the complementary channels. We also give necessary and…

Quantum Physics · Physics 2010-11-23 A. S. Holevo

Quantum channels can represent dynamic resources, which are indispensable elements in many physical scenarios. To describe certain facets of nonclassicality of the channels, it is necessary to quantify their properties. In the framework of…

Quantum Physics · Physics 2022-11-23 Huaqi Zhou , Ting Gao , Fengli Yan

We start with a short introduction to the roof concept. An elementary discussion of phase-damping channels shows the role of anti-linear operators in representing their concurrence. A general expression for some concurrences is derived. We…

Quantum Physics · Physics 2007-05-23 Armin Uhlmann

Entanglement concurrence is an important bipartite entanglement measure that has found wide applications in quantum technologies. In this work, inspired by unified entropy, we introduce a two-parameter family of entanglement measures,…

Quantum Physics · Physics 2026-02-02 Chen-Ming Bai , Yu Luo

We define the concurrence hierarchy as d-1 independent invariants under local unitary transformations in d-level quantum system. The first one is the original concurrence defined by Wootters et al in 2-level quantum system and generalized…

Quantum Physics · Physics 2009-11-07 Heng Fan , Keiji Matsumoto , Hiroshi Imai

It is shown that the entanglement-structure of 3- and 4-qubit states can be characterized by optimized operators of the Mermin-Klyshko type. It is possible to discriminate between pure 2-qubit entanglements and higher entanglements. A…

Quantum Physics · Physics 2009-11-10 J. Endrejat , H. Buettner

Experimental determination of entanglement is important not only to characterize the state and use it in quantum information, but also in understanding complicated phenomena such as phase transitions. In this paper we show that in many…

Quantum Physics · Physics 2016-01-20 Gaurav Chaudhary , V. Ravishankar

The concurrence, a quantitative measure of the entanglement between a pair of particles, is determined for the case where the pair is extracted from a symmetric state of N two-level systems. Examples are given for both pure and mixed states…

Quantum Physics · Physics 2009-11-07 Xiaoguang Wang , Klaus Molmer

Two measures of entanglement, negativity and concurrence are studied for two arbitrary qudits. We obtain negativity as an expectation value of an operator. The differences of the squares of negativity and concurrence are invariants of…

Quantum Physics · Physics 2007-05-23 Suranjana Rai , Jagdish R. Luthra

This paper explores communication over a two-sender, two-receiver classical interference channel, enhanced by the availability of entanglement resources between transmitters. The central contributions are an inner and outer bound on the…

Quantum Physics · Physics 2025-01-24 Jonas Hawellek , Athin Mohan , Hadi Aghaee , Christian Deppe

We prove that the entangling capacity of a two-qubit unitary operator without local ancillas, both with and without the restriction to initial product states, as quantified by the maximum attainable concurrence, is directly related to the…

Quantum Physics · Physics 2016-09-08 Anthony Chefles

We present a constructive method utilizing the Cartan decomposition to characterize topological properties and their connection to two-qubit quantum entanglement, in the framework of the tenfold classification and Wootters' concurrence.…

Quantum Physics · Physics 2025-02-05 Nadav Orion , Eric Akkermans

Problem of classification of parallel quantum channels for information transfer is studied by method of ladder operators. Detailed compared to http://arxiv.org/abs/quant-ph/0702076 presentation of method of ladder operators is given.…

Quantum Physics · Physics 2008-07-02 Constantin V. Usenko

In this paper, we introduce a category of one-parameter bipartite entanglement quantifiers, termed $G_q$-concurrence ($q>1$), and show rigorously that they satisfy all the axiomatic conditions of an entanglement measure and can be…

Quantum Physics · Physics 2024-06-28 Hui Li , Ting Gao , Fengli Yan

Quantum entanglement is a crucial resource in quantum information processing, advancing quantum technologies. The greater the uncertainty in subsystems' pure states, the stronger the quantum entanglement between them. From the dual form of…

Quantum Physics · Physics 2026-01-01 Dong-Ping Xuan , Zhong-Xi Shen , Wen Zhou , Zhi-Xi Wang , Shao-Ming Fei

Two measures of entanglement, negativity and concurrence are studied for two qutrits. An operator origin of negativity is presented and an analytic formula connecting the two measures is derived.

Quantum Physics · Physics 2007-05-23 Suranjana Rai , Jagdish R. Luthra

A simplified expression of concurrence for two-qubit mixed state having no more than three non-vanishing eigenvalues is obtained. Basing on SU(2) coherent states, the amount of entanglement of two-qubit pure states is studied and conditions…

Quantum Physics · Physics 2012-04-06 S. Salimi , A. Mohammadzade , K. Berrada

We establish a relation between concurrence and entanglement witnesses. In particular, we construct entanglement witnesses for three-qubit W and GHZ states in terms of concurrence and different set of operators that generate it. We also…

Quantum Physics · Physics 2008-06-05 Hoshang Heydari
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