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Quantum entanglement plays a critical role in many quantum applications, but detecting entanglement, especially in multipartite or high-dimensional quantum systems, remains a challenge. In this paper, we propose several families of…

Quantum Physics · Physics 2024-10-15 Yan Hong , Xinlan Hao , Limin Gao

In this study, we introduce an autonomous method for addressing the detection and classification of quantum entanglement, a core element of quantum mechanics that has yet to be fully understood. We employ a multi-layer perceptron to…

Quantum Physics · Physics 2024-10-21 Julio Ureña , Antonio Sojo , Juani Bermejo , Daniel Manzano

We formulate an entanglement criterion using Peres-Horodecki positive partial transpose operations combined with the Schr\"odinger-Robertson uncertainty relation. We show that any pure entangled bipartite and tripartite state can be…

Quantum Physics · Physics 2009-11-13 J. Gillet , T. Bastin , G. S. Agarwal

Localizability of entanglement in fully inseparable states is a key ingredient of assisted quantum information protocols as well as measurement-based models of quantum computing. We investigate the existence of fully inseparable states with…

Quantum Physics · Physics 2017-10-31 M. Mičuda , D. Koutný , M. Miková , I. Straka , M. Ježek , L. Mišta

In an entanglement swapping process two initially uncorrelated qubits become entangled, without any direct interaction. We present a model using local variables aiming at reproducing this remarkable process, under the realistic assumption…

Quantum Physics · Physics 2013-01-22 N. Gisin , B. Gisin

We exhibit an orthogonal set of product states of two three-state particles that nevertheless cannot be reliably distinguished by a pair of separated observers ignorant of which of the states has been presented to them, even if the…

High-dimensional entanglement has been identified as an important resource in quantum information processing, and also as a main obstacle for simulating quantum systems. Its certification is often difficult, and most widely used methods for…

Quantum Physics · Physics 2024-01-31 Shuheng Liu , Matteo Fadel , Qiongyi He , Marcus Huber , Giuseppe Vitagliano

We revisit the genuine multipartite entanglement by a simplified method, which only involves the Schmidt decomposition and local unitary transformation. We construct a local unitary equivalent class of the tri-qubit quantum state, then use…

Quantum Physics · Physics 2023-01-18 Naihuan Jing , Meiming Zhang

Many-particle entanglement is a fundamental concept of quantum physics that still presents conceptual challenges. While spin-squeezed and other nonclassical states of atomic ensembles were used to enhance measurement precision in quantum…

Quantum Physics · Physics 2018-11-09 Matteo Fadel , Tilman Zibold , Boris Décamps , Philipp Treutlein

We present several entanglement conditions in order to detect bound entangled states in continuous variable systems. Specifically, Werner and Wolf [Phys. Rev. Lett. 86, 3658 (2001)] and Horodecki and Lewenstein [Phys. Rev. Lett. 85, 2657…

Quantum Physics · Physics 2015-05-19 Cheng-Jie Zhang , Hyunchul Nha , Yong-Sheng Zhang , Guang-Can Guo

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

For general bipartite mixed states, a sufficient and necessary mathematical condition for certifying entanglement and/or (Bell) non-locality remains unknown. In this paper, we examine this question for a broad and physically relevant class…

Quantum Physics · Physics 2025-03-24 Alexander Bernal , J. Alberto Casas , Juan Falceto

We present a general argument showing that the temperature as well as other thermodynamical state variables can qualify as entanglement witnesses for spatial entanglement. This holds for a variety of systems and we exemplify our ideas using…

Quantum Physics · Physics 2007-05-23 Janet Anders , Dagomir Kaszlikowski , Christian Lunkes , Toshio Ohshima , Vlatko Vedral

We prove experimentally the predicted existence of a three-qubit quantum state with genuine multipartite entanglement which can be certified solely from its separable two-qubit reduced density matrices. The qubits are encoded into different…

Quantum Physics · Physics 2020-08-05 Michal Mičuda , Robert Stárek , Jan Provazník , Olga Leskovjanová , Ladislav Mišta,

First, we show how the quantum circuits for generating and measuring multi-party entanglement of qubits can be translated to continuous quantum variables. We derive sufficient inseparability criteria for $N$-party continuous-variable states…

Quantum Physics · Physics 2007-05-23 Peter van Loock , Samuel L. Braunstein

We use quantum entanglement witnesses derived from Gaussian operators to study the separable criteria of continuous variable states. We transform the validity of a Gaussian witness to a Bosonic Gaussian channel problem. It follows that the…

Quantum Physics · Physics 2022-08-29 Xiao-yu Chen , Maoke Miao , Rui Yin , Jiantao Yuan

Quantum entanglement is usually revealed via a well aligned, carefully chosen set of measurements. Yet, under a number of experimental conditions, for example in communication within multiparty quantum networks, noise along the channels or…

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

The fundamental quantum dynamics of two interacting oscillator systems are studied in two different scenarios. In one case, both oscillators are assumed to be linear, whereas in the second case, one oscillator is linear and the other is a…

Quantum Physics · Physics 2015-06-26 ILki Kim , Gerald J. Iafrate

Standard procedures for entanglement detection assume that experimenters can exactly implement specific quantum measurements. Here, we depart from such idealizations and investigate, in both theory and experiment, the detection of genuine…

Quantum Physics · Physics 2024-10-10 Huan Cao , Simon Morelli , Lee A. Rozema , Chao Zhang , Armin Tavakoli , Philip Walther