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In recent years considerable progress has been made towards developing a general theory of quantum entanglement. In particular, criteria to decide whether a given quantum state is entangled are of high theoretical and practical interest.…

Quantum Physics · Physics 2025-01-27 Shruti Aggarwal

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 propose in this work a practical approach to address the longstanding and challenging problem of quantum separability, leveraging the correlation matrices of generic observables. General separability conditions are obtained by dint of…

Quantum Physics · Physics 2025-05-07 Ma-Cheng Yang , Cong-Feng Qiao

Entanglement is one of the most studied properties of quantum mechanics for its application in quantum information protocols. Nevertheless, detecting the presence of entanglement in large multipartite sates continues to be a great challenge…

Quantum Physics · Physics 2017-06-21 Flavio Baccari , Daniel Cavalcanti , Peter Wittek , Antonio Acín

Separability is an important problem in theory of quantum entanglement. By using the Bloch representation of quantum states in terms of the Heisenberg-Weyl observable basis, we present a new separability criterion for bipartite quantum…

Quantum Physics · Physics 2020-02-04 Jingmei Chang , Meiyu Cui , Tinggui Zhang , Shao-Ming Fei

The quantum separability problem consists in deciding whether a bipartite density matrix is entangled or separable. In this work, we propose a machine learning pipeline for finding approximate solutions for this NP-hard problem in…

Quantum Physics · Physics 2023-12-12 Balthazar Casalé , Giuseppe Di Molfetta , Sandrine Anthoine , Hachem Kadri

Quantumness and separability criteria for continuous variable systems are discussed for the case of a noncommutative (NC) phase-space. In particular, the quantum nature and the entanglement configuration of NC two-mode Gaussian states are…

Quantum Physics · Physics 2015-10-13 Alex E. Bernardini , Catarina Bastos , Orfeu Bertolami , Nuno C. Dias , João N. Prata

Determining whether a quantum state is separable or entangled is a problem of fundamental importance in quantum information science. It has recently been shown that this problem is NP-hard. There is a highly inefficient `basic algorithm'…

Quantum Physics · Physics 2009-11-10 L. M. Ioannou , B. C. Travaglione , D. Cheung , A. K. Ekert

The concept of entangled quantum states is considered in the context of systems of identical particles, based on the requirement that in order to represent physical states both for the overall system and the sub-systems which may be…

Quantum Physics · Physics 2014-01-03 Bryan Dalton , Libby Heaney , John Goold , Thomas Busch , Barry Garraway

Quantum key distribution (QKD) is the most explored application of quantum information theory. A central problem in entanglement-based QKD (EB-QKD), is whether every entangled state can be used to extract a key. We observe that entanglement…

Quantum Physics · Physics 2026-03-09 Shubhayan Sarkar , Tushita Prasad , Karol Horodecki

Entanglement is a physical resource of a quantum system just like mass, charge or energy. Moreover it is an essential tool for many purposes of nowadays quantum information processing, e.g. quantum teleportation, quantum cryptography or…

Disordered Systems and Neural Networks · Physics 2008-02-15 Imre Varga , Jose Antonio Mendez-Bermudez

Entangled systems in experiments may be lost or offline in distributed quantum information processing. This inspires a general problem to characterize quantum operations which result in breaking of entanglement or not. Our goal in this work…

Quantum Physics · Physics 2022-04-21 Ming-Xing Luo , Shao-Ming Fei

We present a description of finite dimensional quantum entanglement, based on a study of the space of all convex decompositions of a given density matrix. On this space we construct a system of real polynomial equations describing separable…

Quantum Physics · Physics 2008-08-27 J. K. Korbicz , F. Hulpke , A. Osterloh , M. Lewenstein

Quantum entanglement plays a key role in quantum computation and quantum information processing. It is of great significance to find efficient and experimentally friend separability criteria to detect entanglement. In this paper, we firstly…

Quantum Physics · Physics 2024-05-09 Yiding Wang , Tinggui Zhang , Xiaofen Huang , Shao-Ming Fei

Quantum entanglement is at the heart of many tasks in quantum information. Apart from simple cases (low dimensions, few particles, pure states), however, the mathematical structure of entanglement is not yet fully understood. This tutorial…

Quantum Physics · Physics 2015-06-26 Dagmar Bruss

We present here an overview of our work concerning entanglement properties of composite quantum systems. The characterization of entanglement, i.e. the possibility to assert if a given quantum state is entangled with others and how much…

Quantum Physics · Physics 2007-05-23 K. Eckert , O. Gühne , F. Hulpke , P. Hyllus , J. Korbicz , J. Mompart , D. Bruß , M. Lewenstein , A. Sanpera

Separability problem is a long-standing tough issue in quantum information theory. In this paper, we propose a general method to detect entanglement via arbitrary measurement $\boldsymbol{X}$, by which several novel criteria are…

Quantum Physics · Physics 2022-08-18 Ma-Cheng Yang , Cong-Feng Qiao

We provide a constructive algorithm to find the best separable approximation to an arbitrary density matrix of a composite quantum system of finite dimensions. The method leads to a condition of separability and to a measure of…

Quantum Physics · Physics 2009-10-30 Maciej Lewenstein , Anna Sanpera

Quantum entanglement is the ability of joint quantum systems to possess global properties (correlation among systems) even when subsystems have no definite individual property. Whilst the 2-dimensional (qubit) case is well-understood,…

Quantum coherence was recently formalized as a physical resource to measure the strength of superposition. Based on the resource theory, we present a systematic framework that connects a coherence measure to the security of quantum key…

Quantum Physics · Physics 2019-06-25 Jiajun Ma , You Zhou , Xiao Yuan , Xiongfeng Ma
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