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Entanglement detection and estimation are fundamental in quantum information science. Compared with discrete-variable states, for which lots of efficient entanglement detection criteria and lower bounds of entanglement measures have been…

Quantum Physics · Physics 2013-11-06 Chengjie Zhang , Sixia Yu , Qing Chen , C. H. Oh

We utilize Kolmogorov-Arnold Networks to design an interpretable model capable of detecting quantum entanglement within a set of nine-parameter two-qubit states. This network serves as an entanglement witness, achieving an accuracy of…

Quantum Physics · Physics 2025-12-09 Fatemeh Lajevardi , Azam Mani , Ali Fahim

Multipartite entanglement is the key resource allowing quantum devices to outperform their classical counterparts, and entanglement certification is fundamental to assess any quantum advantage. The only scalable certification scheme relies…

Quantum Physics · Physics 2021-07-28 Irénée Frérot , Tommaso Roscilde

Recent progress in quantum optics has led to setups that are able to prepare high-dimensional quantum states for quantum information processing tasks. As such, it is of importance to benchmark the states generated by these setups in terms…

Quantum Physics · Physics 2023-03-03 Nikolai Wyderka , Giovanni Chesi , Hermann Kampermann , Chiara Macchiavello , Dagmar Bruß

A convergent iterative procedure is proposed for the calculation of the relative entropy of entanglement of a given bipartite quantum state. When this state turns out to be non-separable the algorithm provides the corresponding optimal…

Quantum Physics · Physics 2009-11-07 Jaroslav Rehacek , Zdenek Hradil

Absolutely separable states form a special subset of the set of all separable states, as they remain separable under any global unitary transformation unlike other separable states. In this work we consider the set of absolutely separable…

Quantum Physics · Physics 2015-06-18 Nirman Ganguly , Jyotishman Chatterjee , A. S. Majumdar

We introduce a new kind of Entanglement Witness which is appropriate for studying genuine multipartite entanglement in large systems. The witness operator has a form that fits naturally to quantum states represented by tensor networks. It…

Quantum Physics · Physics 2019-11-13 Lucas B. Vieira , Diego L. Braga Ferreira , Thiago O. Maciel , Reinaldo O. Vianna

We construct a new class of positive indecomposable maps in the algebra of 'd x d' complex matrices. Each map is uniquely characterized by a cyclic bistochastic matrix. This class generalizes a Choi map for d=3. It provides a new reach…

Quantum Physics · Physics 2008-04-02 Dariusz Chruscinski , Andrzej Kossakowski

We present the general scheme for construction of noiseless networks detecting entanglement with the help of linear, hermiticity-preserving maps. We show how to apply the method to detect entanglement of unknown state without its prior…

Quantum Physics · Physics 2007-11-07 P. Horodecki , R. Augusiak , M. Demianowicz

We show how to detect entangled, bound entangled, and separable bipartite quantum states of arbitrary dimension and mixedness using geometric entanglement witnesses. These witnesses are constructed using properties of the Hilbert-Schmidt…

Quantum Physics · Physics 2009-11-13 Philipp Krammer

Characterizing entanglement of systems composed of multiple particles is a very complex problem that is attracting increasing attention across different disciplines related to quantum physics. The task becomes even more complex when the…

Quantum Physics · Physics 2026-02-12 Shuheng Liu , Qiongyi He , Marcus Huber , Giuseppe Vitagliano

Based on the general form of entanglement witnesses constructed from separable states, we first show a sufficient condition of violating the structural physical approximation (SPA) conjecture [Phys. Rev. A 78, 062105 (2008)]. Then we…

Quantum Physics · Physics 2012-10-15 Bang-Hai Wang , Dong-Yang Long

We introduce a set of electric-field based inequalities capable of detecting multilevel entanglement from a system of N quantum emitters. We determine that the polarization channel as well as the direction of detection can enhance…

Quantum Physics · Physics 2026-02-10 Pedro Rosario , Romain Bachelard

The purpose of an entanglement witness experiment is to certify the creation of an entangled state from a finite number of trials. The statistical confidence of such an experiment is typically expressed as the number of observed standard…

Quantum Physics · Physics 2020-04-29 Bas Dirkse , Matteo Pompili , Ronald Hanson , Michael Walter , Stephanie Wehner

This paper is concerned with all tests for continuous-variable entanglement that arise from linear combinations of second moments or variances of canonical coordinates, as they are commonly used in experiments to detect entanglement. All…

Quantum Physics · Physics 2009-11-11 P. Hyllus , J. Eisert

We present a general strategy to derive entanglement criteria which consists in performing a mapping from qudits to qubits that preserves the separability of the parties and SU(2) rotational invariance. Consequently, it is possible to apply…

Certifying high-dimensional quantum channels is essential for ensuring the reliability of quantum communication protocols. Existing certification schemes often rely on fully trusted internal devices, which is difficult to achieve in…

Quantum Physics · Physics 2026-02-10 Mengyan Li , Yanning Jia , Fenzhuo Guo , Haifeng Dong , Sujuan Qin , Fei Gao

Entanglement is a ubiquitous feature of low temperature systems and believed to be highly relevant for the dynamics of condensed matter properties and quantum computation even at higher temperatures. The experimental certification of this…

Quantum Physics · Physics 2016-01-07 Stefan Bäuml , Dagmar Bruß , Marcus Huber , Hermann Kampermann , Andreas Winter

Preparing and certifying bound entangled states in the laboratory is an intrinsically hard task, due to both the fact that they typically form narrow regions in the state space, and that a certificate requires a tomographic reconstruction…

Quantum Physics · Physics 2018-12-20 Gael Sentís , Johannes N. Greiner , Jiangwei Shang , Jens Siewert , Matthias Kleinmann

The density matrix of composite spin system is discussed in relation to the adjoint representation of unitary group U(n). The entanglement structure is introduced as an additional ingredient to the description of the linear space carrying…

Quantum Physics · Physics 2007-05-23 V. I. Man'ko , G. Marmo , E. C. G. Sudarshan , F. Zaccaria