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The concept of entanglement and separability of quantum states is relevant for several fields in physics. Still, there is a lack of effective operational methods to characterise these features. We propose a method to certify quantum…

Quantum Physics · Physics 2024-03-06 Ties-A. Ohst , Xiao-Dong Yu , Otfried Gühne , H. Chau Nguyen

After introducing the partially separable concept, we proved the equivalence between the partial separability of a given $m$-partite subsystem with $m$ qubits and the purity of states of this $m$-partite subsystem for a pure state in…

Quantum Physics · Physics 2007-05-23 An Min Wang

We review the problem of discriminating entangled states from separable states for bipartite systems. We formally define what entangled states are, present some important criteria to detect entanglement, and show how they can be classified…

Quantum Physics · Physics 2007-05-23 Aditi Sen De , Ujjwal Sen , Maciej Lewenstein , Anna Sanpera

The destruction of entanglement of open quantum systems by decoherence is investigated in the asymptotic long-time limit. Starting from a general and analytically solvable decoherence model which does not involve any weak-coupling or…

Quantum Physics · Physics 2012-03-26 Jaroslav Novotný , Gernot Alber , Igor Jex

The notion of "closed systems" in Quantum Mechanics is discussed. For this purpose, we study two models of a quantum-mechanical system $P$ spatially far separated from the "rest of the universe" $Q$. Under reasonable assumptions on the…

Mathematical Physics · Physics 2015-05-06 Jérémy Faupin , Jürg Fröhlich , Baptiste Schubnel

The distinction between pure states and mixed states is a kernel ingredient of what is considered to be the standard formulation of quantum mechanics and plays today a kernel role in foundational debates about the meaning of quantum…

History and Philosophy of Physics · Physics 2024-11-01 Christian de Ronde , César Massri

We investigate the detection of entanglement in $n$-partite quantum states. We obtain practical separability criteria to identify genuinely entangled and non-separable mixed quantum states. No numerical optimization or eigenvalue evaluation…

Quantum Physics · Physics 2010-12-15 Ting Gao , Yan Hong

Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal ({\em i.e.}referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss of information…

Quantum Physics · Physics 2007-05-23 Gerardo Adesso , Alessio Serafini , Fabrizio Illuminati

Geometric properties of the set of quantum entangled states are investigated. We propose an explicit method to compute the dimension of local orbits for any mixed state of the general K x M problem and characterize the set of effectively…

Quantum Physics · Physics 2009-11-06 Marek Kus , Karol Zyczkowski

For a given pure state of a composite quantum system we analyze the product of its projections onto a set of locally orthogonal separable pure states. We derive a bound for this product analogous to the entropic uncertainty relations. For…

Quantum Physics · Physics 2015-05-28 Łukasz Rudnicki , Paweł Horodecki , Karol Życzkowski

Two or more quantum systems are said to be in an entangled or non-factorisable state if their joint (supposedly pure) wave-function is not expressible as a product of individual wave functions but is instead a superposition of product…

Quantum Physics · Physics 2015-06-26 Thomas Durt

We discuss the question of entanglement versus separability of pure quantum states in direct product Hilbert spaces and the relevance of this issue to physics. Different types of separability may be possible, depending on the particular…

Quantum Physics · Physics 2009-11-07 Jon Eakins , George Jaroszkiewicz

Identical particles and entanglement are both fundamental components of quantum mechanics. However, when identical particles are condensed in a single spatial mode, the standard notions of entanglement, based on clearly identifiable…

Quantum Physics · Physics 2014-04-23 N. Killoran , M. Cramer , M. B. Plenio

Entanglement, or quantum inseparability, is a crucial resource in quantum information applications, and therefore the experimental generation of separated yet entangled systems is of paramount importance. Experimental demonstrations of…

Quantum Physics · Physics 2009-11-07 M. G. Raymer , A. C. Funk , B. C. Sanders , H. de Guise

We show that the separability of states in quantum mechanics has a close counterpart in classical physics, and that conditional mutual information (a.k.a. conditional information transmission) is a very useful quantity in the study of both…

Quantum Physics · Physics 2007-05-23 Robert R. Tucci

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

We give an elementary introduction to the notion of quantum entanglement between distinguishable parties and review a recent proposal about solid state quantum computation with spin-qubits in quantum dots. The indistinguishable character of…

Condensed Matter · Physics 2007-05-23 John Schliemann , Daniel Loss

Although the foundations of quantum and classical physics are much different, it is often difficult to pinpoint which features of a particular system are intrinsically "quantum". Perhapse, the most clear-cut distinction between "classical"…

Quantum Physics · Physics 2015-02-05 Piotr Szańkowski

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 two sets of computable entanglement measures for multipartite systems where each subsystem can have different degrees of freedom (so-called qudits). One set, called 'separability' measure, reveals which of the subsystems are…

Quantum Physics · Physics 2009-06-10 Beatrix C. Hiesmayr , Marcus Huber , Philipp Krammer