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

arXiv:0803.4102 · Physical Review A

Proposal for a loophole-free test of nonlocal realism with electron spins of donors

Fang-Yu Hong, Shi-Jie Xiong

Published May 16, 2008• 2 citations
arXivHTMLPDF

Abstract

The deep-rooted concept of ``realism''---a viewpoint according to which an external reality exists independent of observation, may have been shaken to some extent by a recent surprising advance in experimental test of a broad class of nonlocal hidden-variable (NLHV) theories [S. Gr\"oblacher, T. Paterek, R. Kaltenbaek, \ifmmode \check{C}\else \v{C}\fi{}. Brukner, M. \ifmmode \dot{Z}\else \.{Z}\fi{}ukowski, M. Aspelmeyer, and A. Zeilinger, Nature (London) 446, 871 (2007)], though there exists a detection loophole. In this paper a feasible propose for a loophole-free test of non-local realism is discussed based on the independent readout of two electron spins of donors $^{31}\text{P}$ in semiconductors in different cavities entangled through a 4.4 dB bright squeezed coherent light and a postselection based on homodyne measurement. The electron spins are read out by using optically induced spin to charge transduction detected by radio-frequency single electron transistor.

DOI
10.1103/physreva.77.052113

Related papers

Proposal for a Loophole-Free Bell Test with Electron Spins of Donors in Silicon

Fang-Yu Hong, Shi‐Jie Xiong, Yang Xiang +1 more

So far, all experimental tests of Bell inequalities which must be satisfied by all local realistic hidden-variable theories and are violated by quantum mechanical predictions have left at least one loophole open. We propose a feasible setup allowing for a loophole-free test of the Bell inequalities. Two electron spin qubits of donors31P in a nanoscale silicon host in different cavities 300 m apart are entangled through a bright coherent light and postselections using homodyne measurements. The electron spins are then read out randomly and independently by Alice and Bob, respectively, with unity efficiency in less than 0.7 µs by using optically induced spin to charge transduction detected by radio-frequency single electron transistor. A violation of Bell inequality larger than 37% and 18% is achievable provided that the detection accuracy is 0.99 and 0.95, respectively.

Journal of Modern Physics•Jan 1, 2011•0 citations

A Criticism of the article "An experimental test of non-local realism"

Daniel V. Tausk

I make some critical comments on the article "An experimental test of non-local realism", by S. Groblacher, T. Paterek, R. Kaltenbaek, C. Brukner, M. Zukowski, M. Aspelmeyer, & A. Zeilinger, Nature 446, p. 871-875 (2007). This article makes incorrect claims concerning Bell's theorem. Moreover, I point to the fact that a hypothesis referred to as "realism" in the article (Groblacher et al.) is not used in the deduction of Leggett's inequality.

arXiv:0809.4000•Sep 23, 2008•1 citation

Advanced tests of nonlocality with entangled photons

Bradley Christensen

"In 1935, Einstein, Podolsky, and Rosen questioned whether quantum mechanics can be complete, as it seemingly does not adhere to a natural view of reality: local realism, which is the notion that an event can only be influenced by events in the past lightcone, and can only influence events in the future lightcone. This question sparked a philosophical debate that lasted for three decades, until John Bell demonstrated that not only are quantum mechanics and local realism philosophically incompatible, but they predict different statistical results for an appropriate set of measurements on entangled particles, which changed the debate to a scientific discussion. Since then, Bell inequality violations have occurred in a plethora of systems, hinting that local realism is indeed wrong. However, every experiment had imperfections that complicated the interpretation --- the experiments had so-called ""loopholes"" which allowed local realism to persist. In this manuscript, we present our work in using optimized sources of entangled photons to perform the long-sought loophole-free Bell test. This landmark experiment invalidates local realism to the best that science will allow. Beyond answering questions on reality, these Bell tests have a important application in generating provably-secure private random numbers, which then can be used as a seed for cryptographic applications. Not only do we demonstrate that nonlocality must exist, but we begin an experimental exploration in an attempt to understand and quantify this nonlocality. We do so by considering all theories that obey no-signaling (or relativistic causality). In our experiments, we observe the counter-intuitive feature of measuring more nonlocality with less entangled states. We also place a bound on the predictive power of any theory that obeys relativistic causality. And finally, we are able to measure quantum correlations only attainable through complex qubits. This work merely begins to probe the quantum boundary, beginning a journey that may someday find evidence of a beyond-quantum theory."

•Apr 14, 2016•0 citations

A Criticism of the article

Daniel V. Tausk

I make some critical comments on the article An experimental test of non-local realism, by S. Groblacher, T. Paterek, R. Kaltenbaek, C. Brukner, M. Zukowski, M. Aspelmeyer, & A. Zeilinger, Nature 446, p. 871-875 (2007). This article makes incorrect claims concerning Bell's theorem. Moreover, I point to the fact that a hypothesis referred to as realism in the article (Groblacher et al.) is not used in the deduction of Leggett's inequality.

•Sep 23, 2008•0 citations

Loophole-Free Bell Test Based on Local Precertification of Photon’s Presence

Adán Cabello, Fabio Sciarrino

A first demonstration of quantum nonlocality without loopholes would rule out all local hidden variables theories. Experimental techniques proposed here remove transmission losses as a limitation, showing that loophole-free tests are feasible.

arXiv:1206.2289•Physical Review X•Jun 11, 2012•29 citations

Homodyne detection and optical parametric amplification: a classical approach applied to proposed "loophole-free" Bell tests

Caroline H. Thompson

Recent proposed ``loophole-free'' Bell tests are discussed in the light of classical models for the relevant features of optical parametric amplification and homodyne detection. The Bell tests themselves are uncontroversial: there are no obvious loopholes that might cause bias and hence, if the world does, after all, obey local realism, no violation of a Bell inequality will be observed. Interest centres around the question of whether or not the proposed criterion for ``non-classical'' light is valid. If it is not, then the experiments will fail in their initial concept, since both quantum theorists and local realists will agree that we are seeing a purely classical effect. The Bell test, though, is not the only criterion by which the quantum-mechanical and local realist models can be judged. It is suggested that the quantum-mechanical models given in the proposals will also fail in their detailed predictions. If the experiments are extended by including a range of parameter values and by analysing, in addition to the proposed digitised voltage differences, the raw voltages, the models can be compared in their overall performance and plausibility.

arXiv:quant-ph/0512141•Dec 17, 2005•0 citations
The deep-rooted concept of ``realism''---a viewpoint according to which an external reality exists independent of observation, may have been shaken to some extent by a recent surprising advance in experimental test of a broad class of nonlocal hidden-variable (NLHV) theories [S. Gr"oblacher, T. Paterek, R. Kaltenbaek, \ifmmode \check{C}\else \v{C}\fi{}. Brukner, M. \ifmmode \dot{Z}\else .{Z}\fi{}ukowski, M. Aspelmeyer, and A. Zeilinger, Nature (London) 446, 871 (2007)], though there exists a detection loophole. In this paper a feasible propose for a loophole-free test of non-local realism is discussed based on the independent readout of two electron spins of donors 31P^{31}\text{P}31P in semiconductors in different cavities entangled through a 4.4 dB bright squeezed coherent light and a postselection based on homodyne measurement. The electron spins are read out by using optically induced spin to charge transduction detected by radio-frequency single electron transistor.
So far, all experimental tests of Bell inequalities which must be satisfied by all local realistic hidden-variable theories and are violated by quantum mechanical predictions have left at least one loophole open. We propose a feasible setup allowing for a loophole-free test of the Bell inequalities. Two electron spin qubits of donors31P in a nanoscale silicon host in different cavities 300 m apart are entangled through a bright coherent light and postselections using homodyne measurements. The electron spins are then read out randomly and independently by Alice and Bob, respectively, with unity efficiency in less than 0.7 µs by using optically induced spin to charge transduction detected by radio-frequency single electron transistor. A violation of Bell inequality larger than 37% and 18% is achievable provided that the detection accuracy is 0.99 and 0.95, respectively.
"In 1935, Einstein, Podolsky, and Rosen questioned whether quantum mechanics can be complete, as it seemingly does not adhere to a natural view of reality: local realism, which is the notion that an event can only be influenced by events in the past lightcone, and can only influence events in the future lightcone. This question sparked a philosophical debate that lasted for three decades, until John Bell demonstrated that not only are quantum mechanics and local realism philosophically incompatible, but they predict different statistical results for an appropriate set of measurements on entangled particles, which changed the debate to a scientific discussion. Since then, Bell inequality violations have occurred in a plethora of systems, hinting that local realism is indeed wrong. However, every experiment had imperfections that complicated the interpretation --- the experiments had so-called ""loopholes"" which allowed local realism to persist. In this manuscript, we present our work in using optimized sources of entangled photons to perform the long-sought loophole-free Bell test. This landmark experiment invalidates local realism to the best that science will allow. Beyond answering questions on reality, these Bell tests have a important application in generating provably-secure private random numbers, which then can be used as a seed for cryptographic applications. Not only do we demonstrate that nonlocality must exist, but we begin an experimental exploration in an attempt to understand and quantify this nonlocality. We do so by considering all theories that obey no-signaling (or relativistic causality). In our experiments, we observe the counter-intuitive feature of measuring more nonlocality with less entangled states. We also place a bound on the predictive power of any theory that obeys relativistic causality. And finally, we are able to measure quantum correlations only attainable through complex qubits. This work merely begins to probe the quantum boundary, beginning a journey that may someday find evidence of a beyond-quantum theory."
Recent proposed ``loophole-free'' Bell tests are discussed in the light of classical models for the relevant features of optical parametric amplification and homodyne detection. The Bell tests themselves are uncontroversial: there are no obvious loopholes that might cause bias and hence, if the world does, after all, obey local realism, no violation of a Bell inequality will be observed. Interest centres around the question of whether or not the proposed criterion for ``non-classical'' light is valid. If it is not, then the experiments will fail in their initial concept, since both quantum theorists and local realists will agree that we are seeing a purely classical effect. The Bell test, though, is not the only criterion by which the quantum-mechanical and local realist models can be judged. It is suggested that the quantum-mechanical models given in the proposals will also fail in their detailed predictions. If the experiments are extended by including a range of parameter values and by analysing, in addition to the proposed digitised voltage differences, the raw voltages, the models can be compared in their overall performance and plausibility.