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How the Bell tests changed quantum physics

More than 40 years ago the first Bell tests translated a purely philosophical conundrum to a physical experiment. In doing so, they changed our understanding of quantum mechanics and contributed to the development of quantum technologies.

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Fig. 1: John Bell at CERN around 1982.


  1. Einstein, A., Podolsky, B. & Rosen, N. Can quantum-mechanical description of physical reality be considered complete? Phys. Rev. 47, 777 (1935).

    Article  ADS  Google Scholar 

  2. Freedman, S. J. & Clauser, J. F. Experimental test of local hidden-variable theories. Phys. Rev. Lett. 28, 938 (1972).

    Article  ADS  Google Scholar 

  3. Aspect, A., Grangier, P. & Roger, G. Experimental tests of realistic local theories via Bell’s theorem. Phys. Rev. Lett. 47, 460 (1981).

    Article  ADS  Google Scholar 

  4. Aspect, A., Grangier, P. & Roger, G. Experimental realization of Einstein-Podolsky-Rosen-Bohm gedankenexperiment: a new violation of Bell’s inequalities. Phys. Rev. Lett. 49, 91 (1982).

    Article  ADS  Google Scholar 

  5. Aspect, A., Dalibard, J. & Roger, G. Experimental test of Bell’s inequalities using time-varying analyzers. Phys. Rev. Lett. 49, 1804 (1982).

    Article  ADS  MathSciNet  Google Scholar 

  6. Aspect, A. Closing the door on Einstein and Bohr’s quantum debate. Physics 8, 123 (2015).

    Article  Google Scholar 

  7. Rauch, D. et al. Cosmic Bell test using random measurement settings from high-redshift quasars. Phys. Rev. Lett. 121, 080403 (2018).

    Article  ADS  Google Scholar 

  8. The BIG Bell Test Collaboration. Challenging local realism with human choices. Nature 557, 212–216 (2018).

    Article  ADS  Google Scholar 

  9. Ekert, A. K. Quantum cryptography based on Bell’s theorem. Phys. Rev. Lett. 67, 661 (1991).

    Article  ADS  MathSciNet  Google Scholar 

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Correspondence to Iulia Georgescu.

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Georgescu, I. How the Bell tests changed quantum physics. Nat Rev Phys 3, 674–676 (2021).

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