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Related papers: Separability criteria based on the Bloch represent…

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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 present a novel inequality on the purity of a bipartite state depending solely on the difference of the local Bloch vector lengths. For two qubits this inequality is tight for all marginal states and so extends the previously known…

Quantum Physics · Physics 2024-01-23 Simon Morelli , Christopher Eltschka , Marcus Huber , Jens Siewert

We study genuine tripartite entanglement and multipartite entanglement of arbitrary $n$-partite quantum states by using the representations with generalized Pauli operators of a density matrices. While the usual Bloch representation of a…

Quantum Physics · Physics 2023-10-18 Hui Zhao , Yu-Qiu Liu , Naihuan Jing , Zhi-Xi Wang

We present a framework for deciding whether a quantum state is separable or entangled using covariance matrices of locally measurable observables. This leads to the covariance matrix criterion as a general separability criterion. We…

Quantum Physics · Physics 2008-12-03 Oleg Gittsovich , Otfried Gühne , Philipp Hyllus , Jens Eisert

We study the quantum separability problem by using general symmetric informationally complete measurements and present a separability criterion for arbitrary dimensional bipartite systems. We show by detailed examples that our criterion is…

Quantum Physics · Physics 2018-10-10 Le-Min Lai , Tao Li , Shao-Ming Fei , Zhi-Xi Wang

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

We discuss the problem of determining whether the state of several quantum mechanical subsystems is entangled. As in previous work on two subsystems we introduce a procedure for checking separability that is based on finding state…

Quantum Physics · Physics 2007-05-23 Andrew C. Doherty , Pablo A. Parrilo , Federico M. Spedalieri

We analyze and compare the mathematical formulations of the criterion for separability for bipartite density matrices and the Bell inequalities. We show that a violation of a Bell inequality can formally be expressed as a witness for…

Quantum Physics · Physics 2009-10-31 Barbara M. Terhal

Using new results on the separability properties of bosonic systems, we provide a new complete criterion for separability. This criterion aims at characterizing the set of separable states from the inside by means of a sequence of…

Quantum Physics · Physics 2013-05-29 Miguel Navascues , Masaki Owari , Martin B. Plenio

The so-called permutation separability criteria are simple operational conditions that are necessary for separability of mixed states of multipartite systems: (1) permute the indices of the density matrix and (2) check if the trace norm of…

Quantum Physics · Physics 2007-05-23 Pawel Wocjan , Michal Horodecki

Condition for distinguishability of countably infinite number of pure states by a single measurement is given. Distinguishability is to be understood as possibility of an unambiguous measurement. For finite number of states, it is known…

Quantum Physics · Physics 2016-12-08 Ryuitiro Kawakubo , Tatsuhiko Koike

Mutually unbiased measurements (MUMs) are generalized from the concept of mutually unbiased bases (MUBs) and include the complete set of MUBs as a special case, but they are superior to MUBs as they do not need to be rank one projectors. We…

Quantum Physics · Physics 2015-08-25 Lu Liu , Ting Gao , Fengli Yan

Separability criteria are typically of the necessary, but not sufficient, variety, in that satisfying some separability criterion, such as positivity of eigenvalues under partial transpose, does not strictly imply separability. Certifying…

Quantum Physics · Physics 2014-04-21 Elie Wolfe , S. F. Yelin

We review the criteria for separability and quantum entanglement, both in a bipartite as well as a multipartite setting. We discuss Bell inequalities, entanglement witnesses, entropic inequalities, bound entanglement and several features of…

Quantum Physics · Physics 2007-05-23 Barbara M. Terhal

A general separability condition on the second moment (covariance matrix) for continuous variable two-party systems is derived by an analysis analogous to the derivation of the Kennard's uncertainty relation without referring to the…

Quantum Physics · Physics 2015-05-13 Kazuo Fujikawa

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

Separability from the spectrum is a significant and ongoing research topic in quantum entanglement. In this study, we investigate properties related to absolute separability from the spectrum in qudits-qudits states in the bipartite states…

Quantum Physics · Physics 2024-08-22 Liang Xiong , Nung-Sing Sze

Basing on the analogy between the coherent states of light and separable states of $N$ bosons, we demonstrate that the violation Cauchy-Schwarz inequality for any-order correlation function signals the entanglement among the constituent…

Quantum Physics · Physics 2015-04-24 T. Wasak , P. Szankowski , M. Trippenbach , J. Chwedenczuk

We study bipartite entanglement in systems of N identical bosons distributed in M different modes. For such systems, a definition of separability not related to any a priori Hilbert space tensor product structure is needed and can be given…

Quantum Physics · Physics 2012-03-15 F. Benatti , R. Floreanini , U. Marzolino

The variety of multi-partite entangled states enables numerous applications in novel quantum information tasks. In order to compare the suitability of different states from a theoretical point of view classifications have been introduced.…

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