English
Related papers

Related papers: Clauser-Horne Bell test with imperfect random inpu…

200 papers

Loophole-free Bell tests for quantum nonlocality and long-distance secure communication require photodetection efficiencies beyond a threshold eta_{crit} that depends on the Bell inequality and the noise affecting the entangled state…

The Hardy test of nonlocality can be seen as a particular case of the Bell tests based on the Clauser-Horne (CH) inequality. Here we stress this connection when we analyze the relation between the CH-inequality violation, its threshold…

Quantum Physics · Physics 2015-06-03 G. Lima , E. B. Inostroza , R. O. Vianna , J. -Å. Larsson , C. Saavedra

We discuss the recently observed "loophole free" violation of Bell's inequalities in the framework of a physically realist view of quantum mechanics, which requires that physical properties are attributed jointly to a system, and to the…

Quantum Physics · Physics 2022-01-04 Alexia Auffèves , Philippe Grangier

The no-signalling principle is a fundamental assumption in Bell-inequality and quantum-steering experiments. Nonetheless, experimental imperfections can lead to apparent violations beyond those expected from finite-sample statistics. Here,…

Nonlocality is a fascinating and counterintuitive aspect of Nature, revealed by the violation of a Bell inequality. The standard and easiest configuration in which Bell inequalities can be measured has been proposed by…

Quantum Physics · Physics 2015-03-17 Enrico Pomarico , Jean-Daniel Bancal , Bruno Sanguinetti , Anas Rochdi , Nicolas Gisin

Heisenberg's uncertainty principle, coherence and Bell nonlocality have been individually examined through many experiments. In this Letter, we systematically characterize all of this quantumness in a unified manner. We first construct…

We address the problem of closing the detection efficiency loophole in Bell experiments, which is crucial for real-world applications. Every Bell inequality has a critical detection efficiency $\eta$ that must be surpassed to avoid the…

An experimental test of Bell's inequality allows ruling out any local-realistic description of nature by measuring correlations between distant systems. While such tests are conceptually simple, there are strict requirements concerning the…

We analyze Bell inequalities violations in photonic experiments for which the measurement apparatuses are restricted to homodyne measurements. Through numerical optimization of the Clauser-Horne-Shimony-Holt inequality over homodyne…

Quantum Physics · Physics 2024-02-05 Enky Oudot , Gaël Massé , Xavier Valcarce , Antonio Acín

A recent experiment presented, for photons, the first violation of a Bell inequality closing the fair-sampling loophole, i.e., without having to assume that the sample of measured photons fairly represents the entire ensemble. In this note,…

Quantum Physics · Physics 2013-07-25 Johannes Kofler , Sven Ramelow , Marissa Giustina , Anton Zeilinger

According to Bell's theorem a large class of hidden-variable models obeying Bell's notion of local causality conflict with the predictions of quantum mechanics. Recently, a Bell-type theorem has been proven using a weaker notion of local…

Quantum Physics · Physics 2012-03-05 Samuel Portmann , Adrian Wuethrich

The assumption of measurement independence is required for a local deterministic model to conduct a Bell test. The violation of a Bell inequality by such a model implies that this assumption must be relaxed. The degree to which the…

The problem of closing the detection loophole in Bell tests is investigated in the presence of a limited number of efficient detectors using emblematic multipartite quantum states. To this end, a family of multipartite Bell inequalities is…

Quantum Physics · Physics 2018-08-17 Kamil Kostrzewa , Wieslaw Laskowski , Tamas Vertesi

We show that the "practical" Bell inequalities, which use intensities as the observed variables, commonly used in quantum optics and widely accepted in the community, suffer from an inherent loophole, which severely limits the range of…

Quantum Physics · Physics 2016-10-07 Marek Zukowski , Marcin Wiesniak , Wieslaw Laskowski

Here it is shown that the simplest description of Bell's experiment according to the canon of von Neumann's theory of measurement explicitly assumes the (Quantum Mechanics-language equivalent of the classical) condition of Locality. This…

Quantum Physics · Physics 2020-02-28 Alejandro Hnilo

Device-independent randomness certification based on Bell nonlocality does not require any assumptions about the devices and therefore provides adequate security. Great effort has been made to demonstrate that nonlocality is necessary for…

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

On one side, so far a great part of the evidence accepted as proof of the alleged quantum non-locality relied on inhomogeneous Bell inequalities involving an additional assumption (no-enhancement) whose role had not been sufficiently…

Mathematical Physics · Physics 2015-03-19 David Rodríguez

The use of Bell's theorem in any application or experiment relies on the assumption of free choice or, more precisely, measurement independence, meaning that the measurements can be chosen freely. Here, we prove that even in the simplest…

Quantum Physics · Physics 2016-11-25 Gilles Pütz , Denis Rosset , Tomer Jack Barnea , Yeong-Cherng Liang , Nicolas Gisin

This article provides a comprehensive review of the critical role of detection efficiency in demonstrating non-classicality across various device-independent and semi-device-independent scenarios. The central focus is the detection…