Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

What is Being Measured in Bell-Test Experiments

Gerard van der Ham

Published Sep 1, 2020• 0 citations
OpenAlex

Abstract

In Bell-test experiments the projection of spinvectors of entangled electrons is detected. To get the correct results the perspective of the electrons has to be taken into account. It must also be assumed that electrons of entangled pairs have fixed opposite spin. Based on these assumptions the Quantum Mechanic correlation in Bell-test experiments is perfectly explicable.

Related papers

Correlationin Bell-Test Experiments and Perspective

Gerard van der Ham

Applying perspective, projection and assuming fixed opposite spin, Quantum Mechanic correlation is perfectly explicable. Bell's theorem is not applicable to spin detection of entangled electrons because he didn't assume fixed opposite spin of entangled electrons.

•Sep 1, 2020•0 citations

Model and Method to Explain Correlation in Bell-Test Experiments

Gerard van der Ham

The correlation in Bell-test experiments in relation to elektronspin can be explained according to local-realism. A simple model shows that the position of the detectors respective of the direction of movement of the elektrons define vektorspaces in which the opposit spinvektors of entangled pairs of elektrons are, which give equal spin result. With this model the identification of those vektorspaces and the measuring and counting of the spinvektors can be described. In this way correlation, as it is calculated in quantum theory and found in experiments, is explained.

•Jul 1, 2019•0 citations

Testing entanglement between free-traveling electron-positron pairs

Leyun Gao, Alim Ruzi, Qite Li +2 more

Quantum entanglement is a cornerstone of quantum mechanics. While the entanglement of confined electron pairs has been established early on, the entanglement of free-traveling electron pairs, particularly at high energies, remains largely unexplored due to the substantial challenges involved in measuring the spins of free-traveling electrons. In this study, we investigate the entanglement and the Bell inequality violation of free-traveling electron-positron pairs generated in a fixed-target experiment. This experimental setup facilitates the creation of a controllable source of entangled electron-positron pairs, where entangled events are produced in specific phase spaces. Based on this source and the prior knowledge of the entangled state, we demonstrate the feasibility of measuring the polarization correlations of the entangled e + e − pairs through their individual secondary scatterings off two separate additional targets.

arXiv:2502.07597•Physical review. D/Physical review. D.•May 21, 2025•3 citations

On the Correlation in Bell-test Experiments

Gerard van der Ham

This paper throws a new light on Bell-test experiments. It is analyzed what the results of Bell-test experiments exactly represent and how they come to existance. It turns out that the 'violation of Bell's inequalities' can be accounted for in a logical way and that there is no need for 'spooky action at a distance'. A condition is that spin is a definite property of particles

•Jan 1, 2021•0 citations

Spin cross-correlation experiments in an electron entangler

Arunav Bordoloi, Valentina Zannier, Lucia Sorba +2 more

Abstract Correlations are fundamental in describing many body systems - not only in natural sciences. However, in experiments, correlations are notoriously difficult to assess on the microscopic scale, especially for electron spins. Here, we demonstrate a direct measurement of the spin cross-correlations between the currents of a Cooper pair splitter, an electronic device that emits electrons originating from Cooper pairs in a superconductor. While it is firmly established theoretically that these electron pairs form maximally spin-entangled singlet states with opposite spin projections, no spin correlation experiments have been demonstrated so far. We use ferromagnetic sidegates, compatible with superconducting electronic structures, to individually spin polarize the transmissions of two quantum dots fabricated in the two electronic paths, which act as tunable spin filters. The signals are detected in standard transport and in highly sensitive transconductance experiments. We find that the spin-cross correlation is negative, compatible with spin singlet emission, and deviates from the ideal value mostly due to a finite overlap of the Zeeman split quantum dot states. Our results demonstrate a new route to perform spin auto- and cross correlation experiments in nanometer scaled electronic devices, especially suitable for those relying on magnetic field sensitive superconducting elements, like unconventional, triplet or topologically non-trivial superconductors, or to perform Bell tests with massive particles, like electrons.

arXiv:2203.07970•Nature•Nov 23, 2022•53 citations

A project to measure quantum spin correlations of relativistic electron pairs in Møller scattering

J. Ciborowski, Paweł Caban, Michał Drągowski +5 more

A project to measure quantum spin correlations for relativistic particles with mass is presented. It aims at testing spin observables in relativistic quantum mechanics. The measurement will be performed for pairs of entangled electrons originating from Møller scattering. A double Mott polarimeter, allowing for simultaneous measurement of the spin projections of both electrons, was designed for this purpose.

EPJ Web of Conferences•Jan 1, 2017•3 citations
In Bell-test experiments the projection of spinvectors of entangled electrons is detected. To get the correct results the perspective of the electrons has to be taken into account. It must also be assumed that electrons of entangled pairs have fixed opposite spin. Based on these assumptions the Quantum Mechanic correlation in Bell-test experiments is perfectly explicable.
The correlation in Bell-test experiments in relation to elektronspin can be explained according to local-realism. A simple model shows that the position of the detectors respective of the direction of movement of the elektrons define vektorspaces in which the opposit spinvektors of entangled pairs of elektrons are, which give equal spin result. With this model the identification of those vektorspaces and the measuring and counting of the spinvektors can be described. In this way correlation, as it is calculated in quantum theory and found in experiments, is explained.
Quantum entanglement is a cornerstone of quantum mechanics. While the entanglement of confined electron pairs has been established early on, the entanglement of free-traveling electron pairs, particularly at high energies, remains largely unexplored due to the substantial challenges involved in measuring the spins of free-traveling electrons. In this study, we investigate the entanglement and the Bell inequality violation of free-traveling electron-positron pairs generated in a fixed-target experiment. This experimental setup facilitates the creation of a controllable source of entangled electron-positron pairs, where entangled events are produced in specific phase spaces. Based on this source and the prior knowledge of the entangled state, we demonstrate the feasibility of measuring the polarization correlations of the entangled e + e − pairs through their individual secondary scatterings off two separate additional targets.
Abstract Correlations are fundamental in describing many body systems - not only in natural sciences. However, in experiments, correlations are notoriously difficult to assess on the microscopic scale, especially for electron spins. Here, we demonstrate a direct measurement of the spin cross-correlations between the currents of a Cooper pair splitter, an electronic device that emits electrons originating from Cooper pairs in a superconductor. While it is firmly established theoretically that these electron pairs form maximally spin-entangled singlet states with opposite spin projections, no spin correlation experiments have been demonstrated so far. We use ferromagnetic sidegates, compatible with superconducting electronic structures, to individually spin polarize the transmissions of two quantum dots fabricated in the two electronic paths, which act as tunable spin filters. The signals are detected in standard transport and in highly sensitive transconductance experiments. We find that the spin-cross correlation is negative, compatible with spin singlet emission, and deviates from the ideal value mostly due to a finite overlap of the Zeeman split quantum dot states. Our results demonstrate a new route to perform spin auto- and cross correlation experiments in nanometer scaled electronic devices, especially suitable for those relying on magnetic field sensitive superconducting elements, like unconventional, triplet or topologically non-trivial superconductors, or to perform Bell tests with massive particles, like electrons.