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Related papers: Violating Bell's inequalities in the vacuum

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We consider the entanglement dynamics between two Unruh-DeWitt detectors at rest separated at a distance $d$. This simple model when analyzed properly in quantum field theory shows many interesting facets and helps to dispel some…

Quantum Physics · Physics 2010-04-15 Shih-Yuin Lin , B. L. Hu

Based on the Bell theorem, it has been believed that a theoretical computation of the Bell correlation requires explicit use of an entangled state. Such a physical superposition of light waves occurs in the downconverter sources used in…

Quantum Physics · Physics 2021-01-14 Louis Sica

The precision with which we can measure operators that do not commute with conserved quantities is limited by the need to preserve the associated global symmetries. We show how to construct a local hidden-variable model that violates Bell…

Quantum Physics · Physics 2025-11-11 Alejandro J. Garza , Jonte R. Hance

Arguments are provided for the reality of the quantum vacuum fields. A polarization correlation experiment with two maximally entangled photons created by spontaneous parametric down-conversion is studied in the Weyl-Wigner formalism, that…

Quantum Physics · Physics 2022-12-08 Emilio Santos

We simulate correlation measurements of entangled photons numerically. The model employed is strictly local. The correlation is determined by its classical expression with one decisive difference: we sum up coincidences for each pair…

Quantum Physics · Physics 2007-05-23 W. A. Hofer

Scientific inquiry seeks causal explanations of observed phenomena. The Bell experiment provides a paradigmatic case, revealing correlations between spatially separated systems that no local model can reproduce. Such correlations, known as…

Quantum Physics · Physics 2026-03-03 Mark Broom , Talel Naccache , Emmanuel M. Pothos , Christoph Gallus , Pawel Blasiak

Bell's test, initially devised to distinguish quantum theory from local hidden variable models through {violations of local bounds}, is also a common tool for detecting entanglement. For this purpose, one can assume the quantum description…

Quantum Physics · Physics 2026-04-21 Liang-Liang Sun , Yong-Shun Song , Sixia Yu

The entanglement swapping protocol is analyzed in a relativistic setting, where shortly after the entanglement swapping is performed, a Bell violation measurement is performed. From an observer in the laboratory frame, a Bell violation is…

We derive a set of Bell-type inequalities for arbitrarily high-dimensional systems, based on the assumption of partial separability in the hybrid local-nonlocal hidden variable model. Partially entangled states would not violate the…

Quantum Physics · Physics 2015-05-20 Jing-Ling Chen , Dong-Ling Deng , Hong-Yi Su , Chunfeng Wu , C. H. Oh

We investigate the correlations between any number of arbitrarily far-apart regions of the vacuum of the free Klein-Gordon field by means of its finite duration coupling to an equal number of localized detectors. We show that the…

Quantum Physics · Physics 2009-11-11 J. Silman , B. Reznik

We show, under a very general set of assumptions, that pairs of identical particle detectors in spacelike separation, such as atomic probes, can only harvest entanglement from the vacuum state of a quantum field when they have a non-zero…

Quantum Physics · Physics 2017-06-01 Alejandro Pozas-Kerstjens , Jorma Louko , Eduardo Martin-Martinez

A common experimental strategy for demonstrating non-classical correlations is to show violation of a Bell inequality by measuring a continuously emitted stream of entangled photon pairs. The measurements involve the detection of photons by…

Quantum Physics · Physics 2015-03-11 Emanuel Knill , Scott Glancy , Sae Woo Nam , Kevin Coakley , Yanbao Zhang

Bell inequalities or Bell-like experiments are supposed to test hidden variable theories based on three intuitive assumptions: determinism, locality and measurement independence. If one of the assumptions of Bell inequality is properly…

Quantum Physics · Physics 2018-04-19 R. Rossi , Leonardo A. M. Souza

We investigate quantum correlations appearing for two qubit detectors which are initially uncorrelated and locally coupled to a massless scalar field in a vacuum state. Under the perturbation up to the second order in the coupling, the…

Quantum Physics · Physics 2020-11-09 Akira Matsumura , Yasusada Nambu

We explore the possibility of entanglement detection in continuous variable systems by entanglement witnesses based on covariance matrices, constructible from random homodyne measurements. We propose new linear constraints characterizing…

Quantum Physics · Physics 2021-01-20 Tatiana Mihaescu , Hermann Kampermann , Giulio Gianfelici , Aurelian Isar , Dagmar Bruss

Quantum mechanics admits correlations that cannot be explained by local realistic models. Those most studied are the standard local hidden variable models, which satisfy the well-known Bell inequalities. To date, most works have focused on…

Quantum Physics · Physics 2017-06-01 Dylan J. Saunders , Adam J. Bennet , Cyril Branciard , Geoff J. Pryde

We analyze nonclassical correlations between outcomes of measurements conducted on two spatial radiation modes. These correlations cannot be simulated with statistical mixtures of coherent states or, more generally, with non-negative…

Quantum Physics · Physics 2022-07-01 V. S. Kovtoniuk , I. S. Yeremenko , S. Ryl , W. Vogel , A. A. Semenov

We investigate how entangled inertial Unruh-DeWitt detectors are affected by interaction with a quantum field using a nonperturbative method. Inertial detectors in a $(3+1)$-dimensional Minkowski spacetime with instantaneous switching…

Quantum Physics · Physics 2021-12-28 Kensuke Gallock-Yoshimura , Robert B. Mann

We explore correlations harvesting by two static detectors locally interacting with vacuum massless scalar fields in the presence of an infinite perfectly reflecting boundary. We study the phenomena of mutual information harvesting and…

Quantum Physics · Physics 2023-11-28 Zhihong Liu , Jialin Zhang , Hongwei Yu

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