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We show that quantum computers can be used for producing large $n$-partite nonlocality, thereby providing a method to benchmark them. The main challenges to overcome are as follows: (i) The interaction topology might not allow arbitrary…

Quantum Physics · Physics 2025-01-13 Jan Lennart Bönsel , Otfried Gühne , Adán Cabello

Which nonlocal correlations can be obtained, when a party has access to more than one subsystem? While traditionally nonlocality deals with spacelike separated parties, this question becomes important with quantum technologies that connect…

Quantum Physics · Physics 2023-09-04 Moisés Bermejo Morán , Alejandro Pozas-Kerstjens , Felix Huber

Bell nonlocality is the resource that enables device-independent quantum information processing tasks. It is revealed through the violation of so-called Bell inequalities, indicating that the observed correlations cannot be reproduced by…

Quantum Physics · Physics 2024-09-25 Patrick Emonts , Mengyao Hu , Albert Aloy , Jordi Tura

Suppose we have an unknown multipartite quantum state, how can we experimentally find out whether it is genuine multipartite entangled or not? Recall that even for a bipartite quantum state whose density matrix is known, it is already…

Quantum Physics · Physics 2022-11-16 Zhenyu Chen , Xiaodie Lin , Zhaohui Wei

Non-locality consists in the existence of non-classical correlations between local measurements. So far, it has been investigated mostly in isolated quantum systems. Here we show that non-local correlations are present, can be detected and…

Quantum Physics · Physics 2022-09-01 Carlo Marconi , Andreu Riera-Campeny , Anna Sanpera , Albert Aloy

Nonlocality shapes quantum correlations, revealed through the violation of Bell inequalities. The intersection of all valid Bell inequalities is the so-called local polytope. In multipartite systems, characterizing the local polytope…

Quantum Physics · Physics 2026-01-21 Jin-Fu Chen , Mengyao Hu , Jordi Tura

No-signaling theories, which can contain nonlocal correlations stronger than classical correlations but limited by the no-signaling condition, have deepened our understanding of the quantum theory. In principle, the nonlocality of these…

Quantum Physics · Physics 2016-11-01 Zhu Cao , Tianyi Peng

Quantum information theory has considerably helped in the understanding of quantum many-body systems. The role of quantum correlations and in particular, bipartite entanglement, has become crucial to characterise, classify and simulate…

Quantum Physics · Physics 2018-07-27 Gabriele De Chiara , Anna Sanpera

Quantum entanglement and nonlocality are inextricably linked. However, while entanglement is necessary for nonlocality, it is not always sufficient in the standard Bell scenario. We derive sufficient conditions for entanglement to give rise…

Quantum Physics · Physics 2021-02-22 Patricia Contreras-Tejada , Carlos Palazuelos , Julio I. de Vicente

When three or more particles are considered, quantum correlations can be stronger than the correlations generated by so-called hybrid local hidden variable models, where some of the particles are considered as a single block inside which…

Quantum Physics · Physics 2023-02-13 Fabian Bernards , Otfried Gühne

Apart from the Bell nonlocality, which deals with the correlations generated from the local input-output statistics, quantum theory exhibits another kind of nonlocality that involves the indistiguishability of the locally preparable set of…

Nonlocality, as established by seminal Bell's theorem, is considered to be the most striking feature of correlations present in space like separated events. Its practical application in device independent protocols, such as secure key…

The non-local nature of the correlations possessed by quantum systems may be revealed by experimental demonstrations of the violation of Bell-type inequalities. Recent work has placed bounds on the correlations that quantum systems can…

Quantum Physics · Physics 2020-08-19 Amandeep Singh , Dileep Singh , Vaishali Gulati , Arvind , Kavita Dorai

Nonlocality lies at the core of quantum mechanics from both a fundamental and applicative point of view. It is typically revealed by a Bell test, that is by violation of a Bell inequality, whose success depends both on the state of the…

Quantum Physics · Physics 2010-10-04 Bruno Bellomo , Rosario Lo Franco , Giuseppe Compagno

We provide a novel criterion for identifying quantum correlation, which allows us to find connections between Bell type inequalities, entanglement detection, and correlation. We utilize the criterion to construct witness operators that can…

Quantum Physics · Physics 2007-05-23 Che-Ming Li , Li-Yi Hsu , Wei-Yang Lin , Yueh-Nan Chen , Der-San Chuu , Tobias Brandes

The network structure offers in principle the possibility for novel forms of quantum nonlocal correlations, that are proper to networks and cannot be traced back to standard quantum Bell nonlocality. Here we define a notion of genuine…

Quantum Physics · Physics 2022-08-24 Ivan Šupić , Jean-Daniel Bancal , Yu Cai , Nicolas Brunner

In this paper, combined with infinite time-evolving block decimation (iTEBD) algorithm and Bell-type inequalities, we investigate multi-partite quantum nonlocality in an infinite one-dimensional quantum spin-1/2 XXZ system. High hierarchy…

Techniques developed for device-independent characterizations allow one to certify certain physical properties of quantum systems without assuming any knowledge of their internal workings. Such a certification, however, often relies on the…

Quantum Physics · Physics 2019-07-03 Pei-Sheng Lin , Jui-Chen Hung , Ching-Hsu Chen , Yeong-Cherng Liang

Quantum theory allows for nonlocality without entanglement. Notably, there exist bipartite quantum measurements consisting of only product eigenstates, yet they cannot be implemented via local quantum operations and classical communication.…

Quantum Physics · Physics 2023-07-12 Ivan Šupić , Nicolas Brunner

Contrary to Bell scenario, quantum nonlocality can be exploited even when all the parties do not have freedom to select inputs randomly. Such manifestation of nonlocality is possible in networks involving independent sources. One can…

Quantum Physics · Physics 2020-04-20 Kaushiki Mukherjee , Biswajit Paul , Arup Roy