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For any unitarily invariant convex function F on the states of a composite quantum system which isolates the trace there is a critical constant C such that F(w)<= C for a state w implies that w is not entangled; and for any possible D > C…

Quantum Physics · Physics 2009-11-11 G. A. Raggio

Explicit sufficient and necessary conditions for separability of $N$-dimensional rank two multiparty quantum mixed states are presented. A nonseparability inequality is also given, for the case where one of the eigenvectors corresponding to…

Quantum Physics · Physics 2015-06-26 Shao-Ming Fei , Xiu-Hong Gao , Xiao-Hong Wang , Zhi-Xi Wang , Ke Wu

This paper characterizes two forms of separability of pure states of systems of n qubits: (i) into a tensor product of n qubit states, and (ii), into a tensor product of 2 subsystems states of p and q qubits respectively with p+q=n. For…

Quantum Physics · Physics 2007-05-23 Philippe Jorrand , Mehdi Mhalla

We present a criterion of separability for arbitrary s partitions of N-particle fermionic pure states. We show that, despite the superficial non-factorizability due to the antisymmetry required by the indistinguishability of the particles,…

Quantum Physics · Physics 2010-06-22 Tsubasa Ichikawa , Toshihiko Sasaki , Izumi Tsutsui

In this paper, we present the separability criteria to identify non-$k$-separability and genuine multipartite entanglement in mixed multipartite states using elements of density matrices. Our criteria can detect the non-$k$-separability of…

Quantum Physics · Physics 2015-10-27 N. Ananth , M. Senthilvelan

We discuss the entropic criterion for separability of compound quantum systems for general non-additive entropic forms based on arbitrary concave functions $f$. For any separable state, the generalized entropy of the whole system is shown…

Quantum Physics · Physics 2015-05-20 R. Rossignoli , N. Canosa

We analyze exact ground state (GS) separability in general $N$ particle systems with two-site couplings. General necessary and sufficient conditions for full separability, in the form of one and two-site eigenvalue equations, are first…

Quantum Physics · Physics 2022-03-31 F. Petrovich , N. Canosa , R. Rossignoli

The notion of partial trace of a density operator is essential for the understanding of the entanglement and separability properties of quantum states. In this paper we investigate these notions putting an emphasis on the geometrical…

Quantum Physics · Physics 2023-03-21 Nuno Costa Dias , Maurice de Gosson , Joao Nuno Prata

We present two results on multiqubit Werner states, defined to be those states that are invariant under the collective action of any given single-qubit unitary that acts simultaneously on all the qubits. Motivated by the desire to…

Quantum Physics · Physics 2023-05-10 David W. Lyons , Cristina Mullican , Adam Rilatt , Jack D. Putnam

We study the separability problem in mixtures of Dicke states i.e., the separability of the so-called Diagonal Symmetric (DS) states. First, we show that separability in the case of DS in $C^d\otimes C^d$ (symmetric qudits) can be…

Quantum Physics · Physics 2018-01-16 Jordi Tura , Albert Aloy , Ruben Quesada , Maciej Lewenstein , Anna Sanpera

We have derived a general separability criterion for a class of two mode non-Gaussian continuous variable systems, obtained earlier using PPT, violation of which provides sufficient condition for entanglement. It has been obtained by…

Quantum Physics · Physics 2017-07-21 Prasoon K. Shandilya , Prasanta K. Panigrahi

Quantum entanglement has been regarded as one of the key physical resources in quantum information sciences. However, the determination of whether a mixed state is entangled or not is generally a hard issue, even for the bipartite system.…

Quantum Physics · Physics 2018-02-15 Jun-Li Li , Cong-Feng Qiao

We develop a resource theory for non-absolutely separable states (non-AS) in which absolutely separable states (AS) that cannot be entangled by any global unitaries are recognised as free states and any convex mixture of global unitary…

Quantum Physics · Physics 2023-10-05 Ayan Patra , Arghya Maity , Aditi Sen De

We study the noisy GHZ-W mixture. We demonstrate some necessary but not sufficient criteria for different classes of separability of these states. It turns out that the partial transposition criterion of Peres and the criteria of G\"uhne…

Quantum Physics · Physics 2015-03-17 Szilárd Szalay

We consider the separability of various joint states of D-dimensional quantum systems, which we call "qudits." We derive two main results: (i) the separability condition for a two-qudit state that is a mixture of the maximally mixed state…

Quantum Physics · Physics 2012-01-04 P. Rungta , W. J. Munro , K. Nemoto , P. Deuar , G. J. Milburn , C. M. Caves

The structure and quantification of entanglement in the W-class states are investigated under physically motivated transformations that induce mixed-state dynamics. A rigorous condition is established linking global separability to the…

Quantum Physics · Physics 2025-12-17 Reza Hamzehofi

We study certain quantum states for which the PPT criterion is both sufficient and necessary for separability. A class of $n\times n$ bipartite mixed states is presented and the conditions of PPT for these states are derived. The separable…

Quantum Physics · Physics 2014-01-07 Ting-Gui Zhang , Xiaofen Huang , Xianqing Li-Jost , Naihuan Jing , Shao-Ming Fei

We address perfect discrimination of two separable states. When available states are restricted to separable states, we can theoretically consider a larger class of measurements than the class of measurements allowed in quantum theory. The…

Quantum Physics · Physics 2020-10-08 Hayato Arai , Yuuya Yoshida , Masahito Hayashi

The van der Waals (VDW) equation of state is a simple and popular model to describe the pressure function in equilibrium systems of particles with both repulsive and attractive interactions. This equation predicts an existence of a…

Nuclear Theory · Physics 2015-06-29 V. Vovchenko , D. V. Anchishkin , M. I. Gorenstein

We investigate the separability properties of quantum states described by an extended Werner density matrix, where the classical component exhibits statistical dependence. By generalizing the classical part to allow correlations, we…

General Physics · Physics 2025-07-22 Toru Ohira