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Nonlocality is one of the main characteristic features of quantum systems involving more than one spatially separated subsystems. It is manifested theoretically as well as experimentally through violation of some local realistic inequality.…

Quantum Physics · Physics 2017-02-22 Samir Kunkri , Manik Banik , Sibasish Ghosh

Combining recent advances in superconducting quantum hardware, we explore quantum correlations in a previously inaccessible regime by observing \emph{simultaneously} high-dimensional and many-body Bell non-locality. We report a…

Quantum Physics · Physics 2026-04-28 Yousef Mafi , Ali G. Moghaddam , Teemu Ojanen

Nonlocality, as demonstrated by the violation of Bell inequalities, enables device-independent cryptographic tasks that do not require users to trust their apparatus. In this article, we consider devices whose inputs are spatiotemporal…

Quantum Physics · Physics 2020-02-12 Andrew J. P. Garner , Marius Krumm , Markus P. Mueller

Certification of quantum nonlocality plays a central role in practical applications like device-independent quantum cryptography and random number generation protocols. These applications entail the challenging problem of certifying quantum…

Quantum Physics · Physics 2021-07-21 S. Gómez , D. Uzcategui , I. Machuca , E. S. Gómez , S. P. Walborn , G. Lima , D. Goyeneche

Correlations in quantum networks with independent sources exhibit a completely novel form of nonclassicality in the sense that the nonlocality of such correlations can be demonstrated in fixed local input scenarios. Before the pioneering…

Quantum Physics · Physics 2023-03-16 Kaushiki Mukherjee

Bell correlations are among the most exotic phenomena through which quantum mechanics manifests itself. Their presence signals that the system can violate the postulates of local realism, once believed to be the nonnegotiable property of…

Quantum Physics · Physics 2024-03-06 Danish Ali Hamza , Jan Chwedeńczuk

Based on the new general framework for the probabilistic description of experiments, introduced in quant-ph/0305126, quant-ph/0312199, we analyze in mathematical terms the link between the validity of Bell-type inequalities under joint…

Quantum Physics · Physics 2007-05-23 Elena R. Loubenets

Bell scenarios are multipartite scenarios that exclude any signalling between parties. This leads to a strict hierarchy of classical, quantum, and non-signalling correlations in such scenarios. Here we consider a minimal relaxation of…

Quantum Physics · Physics 2025-07-01 Ravi Kunjwal , Ognyan Oreshkov

A Bell test separates quantum mechanics from a classical, local realist theory of physics. However, a Bell test cannot separate quantum physics from all classical theories. Classical devices supplemented with non-signaling correlations,…

Quantum Physics · Physics 2017-06-08 Rui Chao , Ben W. Reichardt

The self-testing protocols refer to novel device-independent certification schemes wherein the devices are uncharacterised, and the dimension of the system remains unspecified. The optimal quantum violation of a Bell's inequality…

Quantum Physics · Physics 2024-08-21 Rajdeep Paul , Souradeep Sasmal , A. K. Pan

Losses in the transmission channel, which increase with distance, pose a major obstacle to photonics demonstrations of quantum nonlocality and its applications. Recently, Chaturvedi, Viola, and Pawlowski (CVP) [arXiv:2211.14231] introduced…

Quantum Physics · Physics 2024-05-08 Edwin Peter Lobo , Jef Pauwels , Stefano Pironio

Using Bell-inequalities as a tool to explore non-classical physical behaviours, in this paper we analyze what one can expect to find in many-body quantum physics. Concretely, framing the usual correlation scenarios as a concrete…

Quantum Physics · Physics 2021-11-03 Carlos H. S. Vieira , Cristhiano Duarte , Raphael C. Drumond , Marcelo Terra Cunha

We show that, assuming that quantum mechanics holds locally, the finite speed of information is the principle that limits all possible correlations between distant parties to be quantum mechanical as well. Local quantum mechanics means that…

Quantum Physics · Physics 2010-04-28 H. Barnum , S. Beigi , S. Boixo , M. B. Elliott , S. Wehner

Self-testing refers to the possibility of characterizing uniquely (up to local isometries) the state and measurements contained in quantum devices, based only on the observed input-output statistics. Already in the basic case of the…

Quantum Physics · Physics 2016-02-29 Yukun Wang , Xingyao Wu , Valerio Scarani

Understanding the quantitative relation between entanglement and Bell nonlocality is a long-standing open problem of fundamental and practical interest. Here, we tackle this problem in a general Bell scenario. {We observe that lying in the…

Quantum Physics · Physics 2026-04-21 Liang-Liang Sun , Xiang Zhou , Zhen-Peng Xu , Sixia Yu

The outcomes of measurements on entangled quantum systems can be nonlocally correlated. However, while it is easy to write down toy theories allowing arbitrary nonlocal correlations, those allowed in quantum mechanics are limited. Quantum…

Quantum Physics · Physics 2015-03-17 Peter Janotta , Christian Gogolin , Jonathan Barrett , Nicolas Brunner

The unique entanglement measure is concurrence in a 2-qubit pure state. The maximum violation of Bell's inequality is monotonically increasing for this quantity. Therefore, people expect that pure state entanglement is relevant to the…

Quantum Physics · Physics 2022-12-14 Xingyu Guo , Chen-Te Ma

We consider the problem of characterizing the set of input-output correlations that can be generated by an arbitrarily given quantum measurement. Our main result is to provide a closed-form, full characterization of such a set for any qubit…

Quantum Physics · Physics 2017-06-26 Michele Dall'Arno , Sarah Brandsen , Francesco Buscemi , Vlatko Vedral

Violation of Bell inequality (or, Bell-type inequalities) by nonlocal correlations is justified by relaxation of at least one of the plausible physical constraints used to model such inequality. Based on this fact, in this letter we present…

Quantum Physics · Physics 2015-12-31 Biswajit Paul , Kaushiki Mukherjee , Debasis Sarkar

We analyze device-dependent correlation sets generated by fixed local dichotomic measurements for two-qubit systems in the $(2,m,2)$ Bell scenario. We consider three fundamental state spaces for the composite system: the separable state…

Quantum Physics · Physics 2026-04-28 Ryosuke Nogami , Jaeha Lee