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A general scheme to seek for the relations between entanglement and bservables is proposed in principle. In two-qubit systems with enough general Hamiltonian, we find the entanglement to be the functions of observables for six kinds of…

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

We present a notion of generalized entanglement which goes beyond the conventional definition based on quantum subsystems. This is accomplished by directly defining entanglement as a property of quantum states relative to a distinguished…

Quantum Physics · Physics 2007-05-23 Lorenza Viola , Howard Barnum , Emanuel Knill , Gerardo Ortiz , Rolando Somma

A bipartite quantum channel represents the interaction between systems, generally allowing for exchange of information. A special class of bipartite channels are the no-signaling ones, which do not allow communication. In Ref. [1] it has…

Quantum Physics · Physics 2011-01-28 Giacomo Mauro D'Ariano , Stefano Facchini , Paolo Perinotti

Distilling highly entangled quantum states from weaker ones is a process that is crucial for efficient and long-distance quantum communication, and has implications for several other quantum information protocols. We introduce the notion of…

Quantum Physics · Physics 2017-10-17 Tamoghna Das , Asutosh Kumar , Amit Kumar Pal , Namrata Shukla , Aditi Sen De , Ujjwal Sen

Recently, it has been shown that the massless quantum vacuum state contains entanglement between timelike separated regions of spacetime, in addition to the entanglement between the spacelike separated regions usually considered. Here, we…

Quantum Physics · Physics 2015-03-17 S. Jay Olson , Timothy C. Ralph

A recent general model of entanglement, [5], that goes much beyond the usual one based on tensor products of vector spaces is further developed here. It is shown that the usual Cartesian product can be seen as two extreme particular…

General Physics · Physics 2008-07-10 Elemer E Rosinger

The notion of entanglement can be naturally extended from quantum-states to the level of general quantum evolutions. This is achieved by considering multi-partite unitary transformations as elements of a multi-partite Hilbert space and then…

Quantum Physics · Physics 2011-04-14 Paolo Zanardi

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we study the continuous variable entanglement for a system consisting of two independent harmonic oscillators interacting with a…

Quantum Physics · Physics 2009-12-31 Aurelian Isar

The distribution of entanglement between macroscopically separated parties represents a crucial protocol for future quantum information networks. Surprisingly, it has been theoretically shown that two distant systems can be entangled by…

We discuss recent progress in the study of entanglement within cosmological frameworks, focusing on both momentum and position-space approaches and also reviewing the possibility to directly extract entanglement from quantum fields.…

General Relativity and Quantum Cosmology · Physics 2025-11-12 Alessio Belfiglio , Orlando Luongo , Stefano Mancini

Non-Gaussian entangled states play a crucial role in harnessing quantum advantage in continuous-variable quantum information. However, how to fully characterize N-partite (N > 3) non-Gaussian entanglement without quantum state tomography…

Quantum Physics · Physics 2023-12-05 Da Zhang , David Barral , Yanpeng Zhang , Kamel Bencheikh

I consider deterministic distinguishability of a set of orthogonal, bipartite states when only a single copy is available and the parties are restricted to local operations and classical communication, but with the additional requirement…

Quantum Physics · Physics 2009-11-13 Scott M. Cohen

In a bipartite system subject to decoherence from two separate reservoirs, the entanglement is typically destroyed faster than for single reservoirs. Surprisingly however, the existence of separate reservoirs can also have a beneficial…

Quantum Physics · Physics 2010-03-01 Jian Li , G. S. Paraoanu

Entanglement of spatially separated quantum states is usually defined with respect to a reference frame provided by some external observer. Thus, if one wishes to localize the quantum information within a spatially separated entangled…

Quantum Physics · Physics 2023-07-05 Adam Dukehart , David Mattingly

We examine when it is possible to locally extract energy from a bipartite quantum system in the presence of strong coupling and entanglement, a task which is expected to be restricted by entanglement in the low-energy eigenstates. We fully…

Discrete-time quantum walks provide a natural framework for quantum transport on complex networks. On regular structures, coin-walker entanglement has been widely used to characterize quantum transport and to support quantum algorithmic…

Quantum Physics · Physics 2026-05-04 Pravy Prerana , Sascha Wald

We study when a physical operation can produce entanglement between two systems initially disentangled. The formalism we develop allows to show that one can perform certain non-local operations with unit probability by performing local…

Quantum Physics · Physics 2009-11-06 J. I. Cirac , W. Dür , B. Kraus , M. Lewenstein

The entanglement criterion for continuous variable systems and the conditions under which the uncertainty relations are fulfilled are generalized to the case of a noncommutative (NC) phase-space. The quantum nature and the separability of…

Multipartite entanglement is of important resources for quantum communication and quantum computation. Our goal in this paper is to characterize general multipartite entangled states according to shallow quantum circuits. We firstly prove…

Quantum Physics · Physics 2022-12-13 Ming-Xing Luo , Shao-Ming Fei

We construct a class of entangled states in $\mathcal{H}=\mathcal{H}_{A}\otimes\mathcal{H}_{B}\otimes\mathcal{H}_{C}$ quantum systems with $dim\mathcal{H}_{A}=dim\mathcal{H}_{B}=dim\mathcal{H}_{C}=2$ and classify those states with respect…

Quantum Physics · Physics 2015-09-25 Hui Zhao , Xinyu Yu , Naihuan Jing