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We prove that any three linearly independent pure quantum states can always be locally distinguished with nonzero probability regardless of their dimension, entanglement, or multipartite structure. Almost always, all three states can be…

Quantum Physics · Physics 2015-06-26 Somshubhro Bandyopadhyay , Jonathan Walgate

We investigate the separability of arbitrary dimensional tripartite sys- tems. By introducing a new operator related to transformations on the subsystems a necessary condition for the separability of tripartite systems is presented.

Quantum Physics · Physics 2008-09-08 Ming Li , Shao-Ming Fei , Zhi-Xi Wang

The concept of entanglement and separability of quantum states is relevant for several fields in physics. Still, there is a lack of effective operational methods to characterise these features. We propose a method to certify quantum…

Quantum Physics · Physics 2024-03-06 Ties-A. Ohst , Xiao-Dong Yu , Otfried Gühne , H. Chau Nguyen

We derive a separability criterion for bipartite quantum systems which generalizes the already known criteria. It is based on observables having generic commutation relations. We then discuss in detail the relation among these criteria.

Quantum Physics · Physics 2009-11-07 Vittorio Giovannetti , Stefano Mancini , David Vitali , Paolo Tombesi

We propose a new criterion to judge zero quantum discord for arbitrary bipartite states. A bipartite quantum state has zero quantum discord if and only if all blocks of its density matrix are normal matrices and commute with each other.…

Quantum Physics · Physics 2015-03-19 Jie-Hui Huang , Lei Wang , Shi-Yao Zhu

We derive a family of necessary separability criteria for finite-dimensional systems based on inequalities for variances of observables. We show that every pure bipartite entangled state violates some of these inequalities. Furthermore, a…

Quantum Physics · Physics 2016-09-08 Otfried Guehne

We provide necessary and sufficient conditions for separability of mixed states. As a result we obtain a simple criterion of separability for $2\times2$ and $2\times3$ systems. Here, the positivity of the partial transposition of a state is…

Quantum Physics · Physics 2009-10-30 Michal Horodecki , Pawel Horodecki , Ryszard Horodecki

We investigate the separability of quantum states based on covariance matrices. Separability criteria are presented for multipartite states. The lower bound of concurrence proposed in Phys. Rev. A. 75, 052320 (2007) is improved by…

Quantum Physics · Physics 2009-09-29 Ming Li , Shao-Ming Fei , Zhi-Xi Wang

The problem of optimally discriminating between two completely unknown qubit states is generalized by allowing an error margin. It is visualized as a device---the programmable discriminator---with one data and two program ports, each fed…

Quantum Physics · Physics 2013-11-11 G. Sentís , E. Bagan , J. Calsamiglia , R. Muñoz-Tapia

As one of the most profound features of quantum mechanics, entanglement is a vital resource for quantum information processing. Inspired by the recent work on PT-moments and separablity [Phys. Rev. Lett. {\bf 127}, 060504 (2021)], we…

Quantum Physics · Physics 2024-02-21 Xiaofen Huang , Naihuan Jing

Quantum entanglement is the core resource in quantum information processing and quantum computing. It is an significant challenge to effectively characterize the entanglement of quantum states. Recently, elegant separability criterion is…

Quantum Physics · Physics 2023-02-22 Tinggui Zhang , Naihuan Jing , Shao-Ming Fei

In a recent paper (quant-ph/0102133) Chen, Liang, Li and Huang suggest a necessary and sufficient separability criterion, which is supposedly practical in judging the separability of any mixed state. In this note we briefly recapitulate…

Quantum Physics · Physics 2007-05-23 T. Eggeling , K. G. H. Vollbrecht , M. M. Wolf

We introduce a new technique to detect separable states using semidefinite programs. This approach provides a sufficient condition for separability of a state that is based on the existence of a certain local linear map applied to a known…

Quantum Physics · Physics 2009-11-13 Federico M. Spedalieri

Quantum state discrimination is a fundamental concept in quantum information theory, which refers to a class of techniques to identify a specific quantum state through a positive operator-valued measure. In this work, we investigate how…

Quantum Physics · Physics 2025-07-09 Hyunho Cha , Jungwoo Lee

The notion of a qubit is ubiquitous in quantum information processing. In spite of the simple abstract definition of qubits as two-state quantum systems, identifying qubits in physical systems is often unexpectedly difficult. There are an…

Quantum Physics · Physics 2009-11-07 Lorenza Viola , Emanuel Knill , Raymond Laflamme

We study the separability of bipartite quantum systems in arbitrary dimensions using the Bloch representation of their density matrix. This approach enables us to find an alternative characterization of the separability problem, from which…

Quantum Physics · Physics 2024-12-05 Julio I. de Vicente

The entanglement detection via local measurements can be experimentally implemented. Based on mutually unbiased measurements and general symmetric informationally complete positive-operator-valued measures, we present separability criteria…

Quantum Physics · Physics 2018-03-30 Shu-Qian Shen , Ming Li , Xianqing Li-Jost , Shao-Ming Fei

In this paper, the realignment criterion and the RCCN criterion of separability for states in infinite-dimensional bipartite quantum systems are established. Let $H_A$ and $H_B$ be complex Hilbert spaces with $\dim H_A\otimes H_B=+\infty$.…

Quantum Physics · Physics 2010-09-02 Yu Guo , Jinchuan Hou

We explain several separability criteria which rely on uncertainty relations. For the derivation of these criteria uncertainty relations in terms of variances or entropies can be used. We investigate the strength of the separability…

Quantum Physics · Physics 2009-11-10 Otfried Guehne , Maciej Lewenstein

A conceptually simpler proof of the separability criterion for two-qubit systems, which is referred to as "Hefei inequality" in literature, is presented. This inequality gives a necessary and sufficient separability criterion for any mixed…

Quantum Physics · Physics 2017-04-03 Kazuo Fujikawa , C. H. Oh