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We put forward complementary relations of entanglement, coherence, steering inequality violation, and Bell nonlocality for arbitrary three-qubit states. We show that two families of genuinely entangled three-qubit pure states with single…

Quantum Physics · Physics 2023-05-24 Dong-Dong Dong , Xue-Ke Song , Xiao-Gang Fan , Liu Ye , Dong Wang

Probabilities of measurement outcomes of two-particle entangled states give a physically transparent interpretation of the concurrence and of the I-concurrence as entanglement measures. The (I)-concurrence can thus be measured…

Quantum Physics · Physics 2009-11-11 Markus A. Cirone

This paper presents properties of the so-called quasi-Bell states: entangled states written as superpositions of nonorthogonal states. It is shown that a special class of those states, namely entangled coherent states, are more robust…

Quantum Physics · Physics 2007-05-23 Osamu Hirota , Steven J. van Enk , Kazuo Nakamura , Masaki Sohma , Kentaro Kato

Starting from several copies of bipartite noisy entangled states, we design a global and optimal local measurement-based protocol in one- and two-dimensional lattices by which any two or more prefix sites can be connected via entanglement.…

Quantum Physics · Physics 2021-01-04 Ratul Banerjee , Srijon Ghosh , Shiladitya Mal , Aditi Sen De

We consider Bell tests in which the distant observers can perform local filtering before testing a Bell inequality. Notably, in this setup, certain entangled states admitting a local hidden variable model in the standard Bell scenario can…

Quantum Physics · Physics 2016-12-01 Flavien Hirsch , Marco Túlio Quintino , Joseph Bowles , Tamás Vértesi , Nicolas Brunner

We consider mixed states of two qubits and show under which global unitary operations their entanglement is maximized. This leads to a class of states that is a generalization of the Bell states. Three measures of entanglement are…

Quantum Physics · Physics 2009-11-06 Frank Verstraete , Koenraad Audenaert , Tijl De Bie , Bart De Moor

Self-interactions and interaction with the environment tend to push quantum systems toward states of maximal entanglement. This is a definition of decoherence. We argue that these maximally entangled states fall into the well-defined…

Quantum Physics · Physics 2022-10-17 Roman V. Buniy , Robert P. Feger , Thomas W. Kephart

We devise a protocol in which general non-classical multipartite correlations produce a physically relevant effect, leading to the creation of bipartite entanglement. In particular, we show that the relative entropy of quantumness, which…

Violation of a Bell inequality guarantees the existence of quantum correlations in a quantum state. A pure bipartite quantum state, having nonvanishing quantum correlation, always violates a Bell inequality. Such correspondence is absent…

Quantum Physics · Physics 2016-07-06 Kunal Sharma , Tamoghna Das , Aditi Sen De , Ujjwal Sen

An entanglement bound based on local measurements is introduced for multipartite pure states. It is the upper bound of the geometric measure and the relative entropy of entanglement. It is the lower bound of minimal measurement entropy. For…

Quantum Physics · Physics 2011-10-07 Li-zhen Jiang , Xiao-yu Chen , Tian-yu Ye

Understanding which entangled states give rise to Bell nonlocality and thus are resourceful in the device-independent framework is a long-stanging unresolved problem. Here we establish the equivalence between genuine entanglement and…

Quantum Physics · Physics 2025-08-26 Owidiusz Makuta , Remigiusz Augusiak

A still widely debated question in the field of relativistic quantum information is whether entanglement and the degree of violation of Bell's inequalities for massive relativistic particles are frame independent or not. At the core of this…

Quantum Physics · Physics 2021-06-16 Lucas F. Streiter , Flaminia Giacomini , Časlav Brukner

We find a single parameter family of genuinely entangled three qubit pure states, called the maximally Bell inequality violating states (MBV), which exhibit maximum Bell inequality violation by the reduced bipartite system for a fixed…

Quantum Physics · Physics 2016-11-30 Palash Pandya , Avijit Misra , Indranil Chakrabarty

We propose a spin-independent scheme to generate and detect two-particle entanglement in a mesoscopic normal-superconductor system. A superconductor, weakly coupled to the normal conductor, generates an orbitally entangled state by…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 P. Samuelsson , E. V. Sukhorukov , M. Buttiker

Quantum entanglement is usually revealed via a well aligned, carefully chosen set of measurements. Yet, under a number of experimental conditions, for example in communication within multiparty quantum networks, noise along the channels or…

We show that the maximum entanglement in a composite system corresponds to the maximum uncertainty and maximum correlation of local measurements.

Quantum Physics · Physics 2007-05-23 Alexander A. Klyachko , Alexander S. Shumovsky

It is now a well-known fact that the correlations arising from local dichotomic measurements on an entangled quantum state may exhibit intrinsically non-classical features. In this paper we delve into a comprehensive study of random…

We demonstrate the relevance of entanglement, Bell inequalities and decoherence in particle physics. In particular, we study in detail the features of the ``strange'' $K^0 \bar K^0$ system as an example of entangled meson--antimeson…

Quantum Physics · Physics 2014-11-18 Reinhold A. Bertlmann

We derive tight quadratic inequalities for all kinds of hybrid separable-inseparable $n$-particle density operators on an arbitrary dimensional space. This methodology enables us to truly derive a tight quadratic inequality as tests for…

Quantum Physics · Physics 2009-11-07 Koji Nagata , Masato Koashi , Nobuyuki Imoto

In some off-resonant cases, the reduced density matrix of two atoms symmetrically coupled with an optical cavity can very approximately approach to maximally entangled mixed states or maximal Bell violation mixed states in their evolution.…

Quantum Physics · Physics 2015-06-26 Shang-Bin Li , Jing-Bo Xu