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Related papers: Optimization of entanglement witnesses

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An entanglement witness (EW) is a Hermitian operator that can distinguish an entangled state from all separable states. We drive and implement a numerical method based on machine learning to create a multipartite EW. Using support vector…

Quantum Physics · Physics 2025-04-28 Mahmoud Mahdian , Zahra Mousavi

Entanglement witnesses (EWs) are a collection of observables that can characterize separable states and, experimentally, estimating EWs can verify entangled states. In this work, we show that a fixed measurement setting on a multipartite…

Quantum Physics · Physics 2026-05-29 Jaemin Kim , Anindita Bera , Dariusz Chruściński , Joonwoo Bae

Entanglement witnesses (EWs) are a versatile tool in the verification of entangled states. The framework of mirrored EW doubles the power of a given EW by introducing its twin -- a mirrored EW -- whereby two EWs related by mirroring can…

Quantum Physics · Physics 2023-07-11 Anindita Bera , Joonwoo Bae , Beatrix C. Hiesmayr , Dariusz Chruściński

Entanglement, a critical resource for quantum information processing, needs to be witnessed in many practical scenarios. Theoretically, witnessing entanglement is by measuring a special Hermitian observable, called entanglement witness…

Quantum Physics · Physics 2016-04-20 Xiao Yuan , Quanxin Mei , Shan Zhou , Xiongfeng Ma

Entanglement witnesses (EWs) are a versatile tool to detect entangled states and characterize related properties of entanglement in quantum information theory. A witness $W$ corresponds to an observable satisfying…

Quantum Physics · Physics 2026-01-19 Jiheon Seong , Anindita Bera , Beatrix C. Hiesmayr , Dariusz Chruscinski , Joonwoo Bae

Two approaches can be utilized to handle the separability problem, finding out whether a given bipartite qudit state is separable or not: a direct procedure on the state space or the effective tool of entanglement witnesses (EWs). This…

Quantum Physics · Physics 2025-08-05 Dariusz Chruściński , Anindita Bera , Joonwoo Bae , Beatrix C. Hiesmayr

We address the problem of optimising entanglement witnesses when a limited fixed set of local measurements can be performed on a bipartite system, thus providing a procedure, feasible also for experiments, to detect entangled states using…

Quantum Physics · Physics 2020-07-01 Alberto Riccardi , Dariusz Chruściński , Chiara Macchiavello

Entanglement witnesses (EW) allow the detection of entanglement in a quantum system, from the measurement of some few observables. They do not require the complete determination of the quantum state, which is regarded as a main advantage.…

Quantum Physics · Physics 2012-02-02 J. G. Filgueiras , T. O. Maciel , R. E. Auccaise , R. O. Vianna , R. S. Sarthour , I. S. Oliveira

Entanglement detection problem is one of the important problem in quantum information theory. Gurvit showed that this problem is NP complete and thus this may be the possible reason that only one criterion is not sufficient to detect all…

Quantum Physics · Physics 2023-01-25 Shruti Aggarwal , Satyabrata Adhikari

Entanglement witnesses (EWs) are a fundamental tool for the detection of entanglement. We study the inertias of EWs, i.e., the triplet of the numbers of negative, zero, and positive eigenvalues respectively. We focus on the EWs constructed…

Quantum Physics · Physics 2020-12-02 Yi Shen , Lin Chen , Li-Jun Zhao

One of the important approaches to detect quantum entanglement is using linear entanglement witnesses EWs. In this paper, by determining the envelope of the boundary hyper-planes defined by a family of linear EWs, a set of powerful…

Quantum Physics · Physics 2009-11-13 M. A. Jafarizadeh , M. Mahdian , A. Heshmati , K. Aghayari

On the basis of linear programming, new sets of entanglement witnesses (EWs) for 3x3 and 4x4 systems are constructed. In both cases, the constructed EWs correspond to the hyperplanes contacting, without intersecting, the related feasible…

Quantum Physics · Physics 2015-05-19 M. A. Jafarizadeh , N. Behzadi , Y. Akbari

In this work, new types of EWs are introduced. They are constructed by using real skew-symmetric operators defined on a single party subsystem of a bipartite dxd system and a maximal entangled state in that system. A canonical form for…

Quantum Physics · Physics 2015-05-19 M. A. Jafarizadeh , N. Behzadi

Verification of entanglement is an important tool to characterize sources and devices for use in quantum computing and communication applications. In a vast majority of experiments entanglement witnesses (EW) are used in order to prove the…

Quantum Physics · Physics 2012-07-02 Juan Miguel Arrazola , Oleg Gittsovich , Norbert Lütkenhaus

Entanglement detection is one of the important problems in quantum information theory. To deal with this problem, many entanglement detection criteria have been proposed. Among the proposed criteria, the detection of entanglement through…

Quantum Physics · Physics 2026-05-06 Sonia , Satyabrata Adhikari

Entanglement witnesses (EWs) constitute one of the most important entanglement detectors in quantum systems. Nevertheless, their complete characterization, in particular with respect to the notion of optimality, is still missing, even in…

Quantum Physics · Physics 2015-05-20 Remigiusz Augusiak , Jordi Tura , Maciej Lewenstein

A new class of entanglement witnesses (EWs) called reduction type entanglement witnesses is introduced, which can detect some multi-qudit entangeled states including PPT ones with Hilbert space of dimension $d_{_{1}}\otimes…

Quantum Physics · Physics 2009-11-13 M. A. Jafarizadeh , G. Najarbashi , H. Habibian

Recently, X. Qi and J. Hou [Phys. Rev. A 85, 022334 (2012)] provided optimal entanglement witnesses without the spanning property. These witnesses are associated to indecomposable positive linear maps, but it is not checked whether partial…

Quantum Physics · Physics 2012-07-25 Kil-Chan Ha

In this work, we present a practical and efficient framework for verifying entangled states when only a tomographically incomplete measurement setting is available-specifically, when access to observables is severely limited. We show how…

We examine various notions related with the optimality for entanglement witnesses arising from Choi type positive linear maps. We found examples of optimal entanglement witnesses which are non-decomposable, but which are not…

Quantum Physics · Physics 2012-09-10 Kil-Chan Ha , Seung-Hyeok Kye
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