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Quantifying experimentally created entanglement could in principle be accomplished by measuring the entire density matrix and calculating an entanglement measure of choice thereafter. Due to the tensor-structure of the Hilbert space, this…

Quantum Physics · Physics 2015-05-18 H. Wunderlich , S. Virmani , M. B. Plenio

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

Genuine high-dimensional entanglement, i.e. the property of having a high Schmidt number, constitutes a resource in quantum communication, overcoming limitations of low-dimensional systems. States with a positive partial transpose (PPT), on…

Quantum Physics · Physics 2018-11-21 Marcus Huber , Ludovico Lami , Cécilia Lancien , Alexander Müller-Hermes

In support of a recent conjecture by Nielsen (1999), we prove that the phenomena of 'incomparable entanglement'--whereby, neither member of a pair of pure entangled states can be transformed into the other via local operations and classical…

Quantum Physics · Physics 2009-11-07 Rob Clifton , Brian Hepburn , Christian Wuthrich

The transition from unitary, reversible von Neumann-Everett quantum processes to non-unitary, irreversible processes and measurements is explored through infinite tensor products interpreted as nested, chained, or iterated Wigner's friend…

Quantum Physics · Physics 2026-01-22 Karl Svozil

In the standard geometric approach to a measure of entanglement of a pure state, $\sin^2\theta$ is used, where $\theta$ is the angle between the state to the closest separable state of products of normalized qubit states. We consider here a…

Quantum Physics · Physics 2007-09-10 D. Ostapchuk , G. Passante , R. Kobes , G. Kunstatter

We introduce a generalization of entanglement based on the idea that entanglement is relative to a distinguished subspace of observables rather than a distinguished subsystem decomposition. A pure quantum state is entangled relative to such…

Quantum Physics · Physics 2009-11-10 Howard Barnum , Emanuel Knill , Gerardo Ortiz , Rolando Somma , Lorenza Viola

Entanglement of formation is an important measure of quantum entanglement. We present an experimental way to measure the entanglement of formation for arbitrary dimensional pure states. The measurement only evolves local quantum mechanical…

Quantum Physics · Physics 2012-01-31 Ming Li , Shao-Ming Fei

Entanglement is known to be a relative notion, defined with respect to the choice of physical observables to be measured (i.e., the measurement setup used). This implies that, in general, the same state can be both separable and entangled…

Quantum Physics · Physics 2013-05-21 Toshihiko Sasaki , Tsubasa Ichikawa , Izumi Tsutsui

The dimensionality of entanglement is a core tenet of quantum information processing, especially quantum communication and computation. While it is natural to think of this dimensionality in finite dimensional systems, many of the…

Quantum Physics · Physics 2025-09-04 Shuheng Liu , Jiajie Guo , Matteo Fadel , Qiongyi He , Marcus Huber , Giuseppe Vitagliano

In this paper we give a general integral representation for separable states in the tensor product of infinite dimensional Hilbert spaces and provide the first example of separable states that are not countably decomposable. We also prove…

Quantum Physics · Physics 2011-11-09 A. S. Holevo , M. E. Shirokov , R. F. Werner

We derive a family of necessary separability criteria for finite-dimensional systems based on inequalities for variances of observables. We show that every pure bipartite entangled state violates some of these inequalities. Furthermore, a…

Quantum Physics · Physics 2016-09-08 Otfried Guehne

Continuous frames and tensor products are important topics in theoretical physics. This paper combines those concepts. We derive fundamental properties of continuous frames for tensor product of Hilbert spaces. This includes, for example,…

Functional Analysis · Mathematics 2022-03-23 Peter Balazs , Nenad Teofanov

Entanglement measures quantify the amount of quantum entanglement that is contained in quantum states. Typically, different entanglement measures do not have to be partially ordered. The presence of a definite partial order between two…

Quantum Physics · Physics 2022-08-30 Danko D. Georgiev , Stanley P. Gudder

It is known that the spatial product of two product systems is intrinsic. Here we extend this result by analyzing subsystems of the tensor product of product systems. A relation with cluster systems is established. In a special case, we…

Functional Analysis · Mathematics 2015-02-12 Mithun Mukherjee

We discuss the detection of entanglement in interacting quantum spin systems. First, thermodynamic Hamiltonian-based witnesses are computed for a general class of one-dimensional spin-1/2 models. Second, we introduce optimal bipartite…

Quantum Physics · Physics 2009-11-10 L. -A. Wu , S. Bandyopadhyay , M. S. Sarandy , D. A. Lidar

We introduce local filters as a means to detect the entanglement of bound entangled states which do not yield to detection by witnesses based on positive (P) maps which are not completely positive (CP). We demonstrate how such…

Quantum Physics · Physics 2017-09-13 Debmalya Das , Ritabrata Sengupta , Arvind

We consider the problem of separability: decide whether a Hermitian operator on a finite dimensional Hilbert tensor product is separable or entangled. We show that the tensor convolution defined for certain mappings on an almost arbitrary…

Mathematical Physics · Physics 2011-06-08 Gabriel Pietrzkowski

It was proposed that the tensor product structure of the Hilbert space is uniquely determined by the Hamiltonian's spectrum, for most finite-dimensional cases satisfying certain conditions. I show that any such method would lead to…

Quantum Physics · Physics 2024-01-18 Ovidiu Cristinel Stoica

A parametrization of multipartite separable states in a finite-dimensional Hilbert space is suggested. It is proved to be a diffeomorphism between the set of zero-trace operators and the interior of the set of separable density operators.…

Quantum Physics · Physics 2015-05-18 Georges Parfionov , Roman R. Zapatrin