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We consider the behaviour of bipartite and tripartite non-locality between fermionic entangled states shared by observers, one of whom uniformly accelerates. We find that while fermionic entanglement persists for arbitrarily large…

Quantum Physics · Physics 2013-05-30 Alexander Smith , Robert B. Mann

By extending the usual two-mode squeezing operator $S_{2}=\exp [ i\lambda (Q_{1}P_{2}+Q_{2}P_{1}) ] $ to the three-mode squeezing operator $S_{3}=\exp {i\lambda [ Q_{1}(P_{2}+P_{3}) +Q_{2}(P_{1}+P_{3}) +Q_{3}(P_{1}+P_{2}) ]} $, we obtain…

Quantum Physics · Physics 2015-05-14 Shuangxi Zhang , Hongchun Yuan , Hongyi Fan

From an operational criterion of physical reality, a quantifier of realism-based nonlocality was recently introduced for two-part quantum states. This measure has shown to capture aspects that are rather different from Bell nonlocality.…

Quantum Physics · Physics 2019-12-11 D. M. Fucci , R. M. Angelo

We investigate the non-local properties of graph states. To this aim, we derive a family of Bell inequalities which require three measurement settings for each party and are maximally violated by graph states. In turn, for each graph state…

Quantum Physics · Physics 2007-05-23 Otfried Guehne , Geza Toth , Philipp Hyllus , Hans J. Briegel

Alice and Bob each have half of a pair of entangled qubits. Bob measures his half and then passes his qubit to a second Bob who measures again and so on. The goal is to maximize the number of Bobs that can have an expected violation of the…

Quantum Physics · Physics 2020-09-02 Peter J. Brown , Roger Colbeck

We generalize the Greenberger-Horne-Zeilinger nonlocality without inequalities argument to cover the case of arbitrary mixed statistical operators associated to three-qubits quantum systems. More precisely, we determine the radius of a ball…

Quantum Physics · Physics 2009-11-13 GianCarlo Ghirardi , Luca Marinatto

In this paper we extend the ladder proof of nonlocality without inequalities for two spin-half particles given by Boschi et al [PRL 79, 2755 (1997)] to the case in which the measurement settings of the apparatus measuring one of the…

Quantum Physics · Physics 2009-11-07 Jose L. Cereceda

The spin is the prime example of a qubit. Encoding and decoding information in the spin qubit is operationally well defined through the Stern-Gerlach set-up in the non-relativistic (i.e., low velocity) limit. However, an operational…

Quantum Physics · Physics 2019-09-04 Flaminia Giacomini , Esteban Castro-Ruiz , Časlav Brukner

Bell's inequality sets a strict threshold for how strongly correlated the outcomes of measurements on two or more particles can be, if the outcomes of each measurement are independent of actions undertaken at arbitrarily distant locations.…

Quantum Physics · Physics 2022-05-24 David I. Kaiser

The quantum theory of a free particle in two dimensions with non-local boundary conditions on a circle is known to lead to surface and bulk states. Such a scheme is here generalized to the quantized Maxwell field, subject to mixed boundary…

High Energy Physics - Theory · Physics 2009-10-31 Giampiero Esposito , Cosimo Stornaiolo

We introduce a geometric framework for studying Bell nonlocality in Hilbert space, where, for a given quantum state, nonlocality is quantified by the distance between the state and the set of local states. This approach applies to any Bell…

We consider tests of Leggett-Garg's macrorealism and of macroscopic local realism, where for spacelike separated measurements the assumption of macroscopic noninvasive measurability is justified by that of macroscopic locality. We give a…

Quantum Physics · Physics 2024-12-03 Manushan Thenabadu , M. D. Reid

Facet inequalities play an important role in detecting the nonlocality of a quantum state. The number of such inequalities depends on the Bell test scenario. With the increase in the number of parties, measurement outcomes, or/and the…

Quantum Physics · Physics 2023-03-20 Arpan Das , Chandan Datta , Pankaj Agrawal

We consider a two-particle/two-setting Bell experiment to visualize the conflict between Bell-\.Zukowski inequality and Bell-Mermin inequality. The experiment is reproducible by local realistic theories which are not rotationally invariant.…

Quantum Physics · Physics 2015-06-26 Koji Nagata , Jaewook Ahn

We study the trade-off relations satisfied by the genuine tripartite nonlocality in multipartite quantum systems. From the reduced three-qubit density matrices of the four-qubit generalized Greenberger-Horne-Zeilinger (GHZ) states and W…

Quantum Physics · Physics 2019-11-19 Li-Jun Zhao , Lin Chen , Yu-Min Guo , Kai Wang , Yi Shen , Shao-Ming Fei

A cat state localized in the right Rindler wedge is employed to study the violation of the Bell-CHSH inequality in a relativistic scalar free Quantum Field Theory. By means of the bounded Hermitian operator $sign(\varphi(f))$, where…

High Energy Physics - Theory · Physics 2026-01-09 M. S. Guimaraes , I. Roditi , S. P. Sorella

We explore the link between two concepts: the level of violation of a Bell inequality by a quantum state and discrimination between two states by means of restricted classes of operations, such as local operations and classical…

Quantum Physics · Physics 2015-07-15 Karol Horodecki , Gláucia Murta

We demonstrate here that for a given mixed multi-qubit state if there are at least two observers for whom mutual Einstein-Podolsky-Rosen steering is possible, i.e. each observer is able to steer the other qubits into two different pure…

We consider a subclass of bipartite CHSH-type Bell inequalities. We investigate operations, which leave their Tsirelson bound invariant, but change their classical bound. The optimal observables are unaffected except for a relative rotation…

Quantum Physics · Physics 2014-10-10 Michael Epping , Hermann Kampermann , Dagmar Bruß

Distinct from the type of local realist inequality (known as the Collins-Gisin-Linden-Massar-Popescu or CGLMP inequality) usually used for bipartite qutrit systems, we formulate a new set of local realist inequalities for bipartite qutrits…

Quantum Physics · Physics 2017-09-18 Debarshi Das , Shounak Datta , Suchetana Goswami , A. S. Majumdar , Dipankar Home