Advertisement

Bell’s Theorem: The Naive View of an Experimentalist

  • Alain Aspect
Chapter

Abstract

It is a very emotional experience to contribute to this book commemorating of John Bell. I first met John in 1975, a few months after reading his famous paper [1]. I had been so strongly impressed by this paper, that I had immediately decided to do my “thèse d’état” — which at that time, in France, could be a really long work — on this fascinating problem. I definitely wanted to carry out an experiment “in which the settings are changed during the flight of the particles”, as suggested in the paper, and I had convinced a young professor at the Institut d’Optique, Christian Imbert, to support my project and to act as my thesis advisor. He had advised me to go first to Geneva, to discuss my proposal with John Bell. I got an appointment without delay, and I showed up in John’s office at CERN, quite nervous. While I explained my planned experiment, he listened silently. Eventually, I stopped talking, and the first question came: “Have you a permanent position?” After my positive answer, he started talking of physics, and he definitely encouraged me, making it clear that he would consider the implementation of variable analysers a fundamental improvement. Remembering this first question reminds me both of his celebrated sense of humour and of the general atmosphere at that time about raising questions on the foundations of quantum mechanics. Quite frequently there was open hostility, and in the best case, irony: “quantum mechanics has been vindicated by such a large amount of work by the smartest theorists and experimentalists; how can you hope to find anything with such a simple scheme, in optics, a science of the 19th century?” In addition to starting the experiment, I had then to develop a line of argument to try to convince the physicists I met (and among them some had to give their opinion about funding my project). After some not so successful attempts at quite sophisticated pleas, I eventually found out that it was much more efficient to explain the very simple and naive way in which I had understood Bell’s theorem. And to my great surprise, that simple presentation was very convincing even with the most theoretically inclined interlocutors. I was lucky enough to be able to present it in front of John Bell himself, and he apparently appreciated it. I am therefore going to explain now how I understood Bell’s theorem twenty five years ago, and I hope to be able to communicate the shock I received, which was so strong that I spent eight years of my life working on this problem.

Keywords

Quantum Mechanic Bell Inequality Coincidence Rate Polarization Correlation Atomic Cascade 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    J.S. Bell, On the Einstein—Podolsky—Rosen Paradox, Phys. 1, 195 (1964)Google Scholar
  2. 2.
    A. Aspect, Experimental tests of Bell’s inequalities in atomic physics, in: At. Phys. 8, Proceedings of the Eighth International Conference on Atomic Physics, I. Lindgren, A. Rosen, S. Svanberg (eds.) (1982)Google Scholar
  3. 3.
    A. Einstein, B. Podolsky, N. Rosen, Can a quantum-mechanical description of physical reality be considered complete? Phys. Rev. 47, 777 (1935)CrossRefzbMATHGoogle Scholar
  4. A. Einstein, B. Podolsky, N. Rosen, Bohr’s answer: N. Bohr, Can a quantum-mechanical description of physical reality be considered complete? Phys. Rev. 48, 696 (1935)Google Scholar
  5. 4.
    D. Bohm, Quantum Theory (Prentice-Hall, Englewoods Cliffs 1951 ). Republished by Dover, New York (1989)Google Scholar
  6. 5.
    D. Bohm, Y. Aharonov, Discussion of experimental proof for the paradox of Einstein, Rosen and Podolsky, Phys. Rev. 108, 1070 (1957)CrossRefGoogle Scholar
  7. 6.
    P.A. Schilp (ed.), A. Einstein Philosopher Scientist (Open Court and Cambridge Univ. Press, Cambridge 1949 )Google Scholar
  8. 7.
    Correspondence between A. Einstein and M. Born. French translation: ( Seuil, Paris, 1972 )Google Scholar
  9. 8.
    J.F. Clauser, M.A. Horne, A. Shimony, R.A. Holt, Proposed experiment to test local hidden-variable theories, Phys. Rev. Lett. 23, 880 (1969)ADSCrossRefGoogle Scholar
  10. 9.
    B. d’Espagnat, Use of inequalities for the experimental test of a general conception of the foundation of microphysics, Phys. Rev. D 11, 1424 (1975)CrossRefGoogle Scholar
  11. L. Hardy, Quantum mechanics, local realistic theories, and Lorentz-invariant realistic theories, Phys. Rev. Lett. 68, 2981 (1992)Google Scholar
  12. 10.
    J.S. Bell, `Introduction to the hidden-variable question’, in: Foundations of Quantums Mechanics, B. d’Espagnat (ed.), ( Academic, New York 1972 )Google Scholar
  13. 11.
    J.F. Clauser, M.A. Horne, Experimental consequences of objective local theories, Phys. Rev. D 10, 526 (1974)CrossRefGoogle Scholar
  14. 12.
    A. Fine, Hidden variables, Joint probability, and the Bell inequalities, Phys. Rev. Lett. 48, 291 (1982)ADSCrossRefGoogle Scholar
  15. 13.
    A. Aspect, Proposed experiment to test separable hidden-variable theories, Phys. Lett. A 54, 117 (1975)ADSCrossRefGoogle Scholar
  16. A. Aspect, Proposed Experiment to test the nonseparability of Quantum Mechanics, Phys. Rev. D 14, 1944 (1976)CrossRefGoogle Scholar
  17. 14.
    A. Aspect, Trois tests expérimentaux des inégalités de Bell par mesure de corrélation de polarization de photons, thèse d’Etat, Orsay (1983)Google Scholar
  18. 15.
    E.S. Fry, Two-photon correlations in atomic transitions, Phys. Rev. A 8, 1219 (1973)CrossRefGoogle Scholar
  19. 16.
    J.F. Clauser, A. Shimony, Bell’s theorem: Experimental tests and implications, Rep. Prog. Phys. 41, 1881 (1978)ADSCrossRefGoogle Scholar
  20. 17.
    S.J. Freedman, J.F. Clauser, Experimental test of local hidden-variable theories, Phys. Rev. Lett. 28, 938 (1972)ADSCrossRefGoogle Scholar
  21. 18.
    F.M. Pipkin, Atomic physics tests of the basics concepts in quantum mechanics, in: Advances in Atomic and Molecular Physics, D.R. Bates and B. Bederson, (eds.), ( Academic, New York 1978 )Google Scholar
  22. 19.
    J.F. Clauser, Experimental investigation of a polarization correlation anomaly, Phys. Rev. Lett. 36, 1223 (1976)ADSCrossRefGoogle Scholar
  23. 20.
    E.S. Fry, R.C. Thompson, Experimental test of local hidden-variable theories, Phys. Rev. Lett. 37, 465 (1976)ADSCrossRefGoogle Scholar
  24. 21.
    A. Aspect, C. Imbert, G. Roger, Absolute measurement of an atomic cascade rate using a two photon coincidence technique. Application to the 4p2 1,50 4s4p 1P1 — 4s2 1So cascade of calcium excited by a two photon absorption, Opt. Commun. 34, 46 (1980)ADSCrossRefGoogle Scholar
  25. 22.
    A. Aspect, P. Grangier, G. Roger, Experimental Tests of Realistic Local Theories via Bell’s Theorem, Phys. Rev. Lett. 47, 460 (1981)ADSCrossRefGoogle Scholar
  26. 23.
    A. Aspect, P. Grangier, G. Roger, Experimental realization of Einstein—PodolskyRosen—Bohm gedankenexperiment: A new violation of Bell’s inequalities, Phys. Rev. Lett. 49, 91 (1982)ADSCrossRefGoogle Scholar
  27. 24.
    P. Grangier, Thèse de troisième cycle, Orsay (1982)Google Scholar
  28. 25.
    A. Aspect, P. Grangier, About resonant scattering and other hypothetical effects in the Orsay atomic-cascade experiment tests of Bell inequalities: A discussion and some new experimental data, Lett. Nuovo Cim. 43, 345 (1985)Google Scholar
  29. 26.
    A. Garrucio, V.A. Rapisarda, Nuovo Cim. A 65, 269 (1981)ADSCrossRefGoogle Scholar
  30. 27.
    A. Aspect, J. Dalibard, G. Roger, Experimental test of Bell’s inequalities using variable analyzers, Phys. Rev. Lett. 49, 1804 (1982)MathSciNetADSCrossRefGoogle Scholar
  31. 28.
    W. Perrie, A.J. Duncan, H.J. Beyer, H. Kleinpoppen, Polarization correlation of the two photons emitted by metastable atomic deuterium: A test of Bell’s inequality, Phys. Rev. Lett. 54, 1790 (1985);ADSCrossRefGoogle Scholar
  32. W. Perrie, A.J. Duncan, H.J. Beyer, H. Kleinpoppen, Polarization correlation of the two photons emitted by metastable atomic deuterium: A test of Bell’s inequality, Phys. Rev. Lett. 54, 2647 (1985)ADSCrossRefGoogle Scholar
  33. 29.
    Y.H. Shih, C.O. Alley, New type of Einstein—Podolsky—Rosen—Bohm experiment using pairs of light quanta produced by optical parametric down conversion, Phys. Rev. Lett. 61, 2921 (1988)ADSCrossRefGoogle Scholar
  34. 30.
    Z.Y. Ou, L. Mandel, Violation of Bell’s inequality and classical probability in a two-photon correlation experiment, Phys. Rev. Lett. 61, 50 (1988)MathSciNetADSCrossRefGoogle Scholar
  35. 31.
    P.G. Kwiat, K. Mattle, H. Weinfurter, A. Zeilinger, New high-intensity source of polarization-entangled photon-pairs, Phys. Rev. Lett. 75, 4337 (1995) Note that the reported violation of Bell’s inequalities by 100 standard deviations relies on a stronger version of the “fair sampling hypothesis” than our second experiment (Sect. 9.9.4), since this experiment uses one channel polarizers and not two channel polarizersGoogle Scholar
  36. 32.
    T.E. Kiess, Y.H. Shih, A.V. Sergienko, C.O. Alley, Einstein—Podolsky—RosenBohm experiment using pairs of light quanta produced by type-II parametric down-conversion, Phys. Rev. Lett. 71, 3893 (1993)ADSCrossRefGoogle Scholar
  37. 33.
    J.D. Franson, Bell inequality for position and time, Phys. Rev. Lett. 62, 2205 (1989)ADSCrossRefGoogle Scholar
  38. 34.
    J. Brendel, E. Mohler, W. Martienssen, Experimental test of Bell’s inequality for energy and time, Europhys. Lett. 20, 575 (1992)Google Scholar
  39. 35.
    P.R. Tapster, J.G. Rarity, P.C.M. Owens, Violation of Bell’s inequality over 4 km of optical fiber, Phys. Rev. Lett. 73, 1923 (1994)ADSCrossRefGoogle Scholar
  40. 36.
    W. Tittel, J. Brendel, T. Herzog, H. Zbinden, N. Gisin, Non-local two-photon correlations using interferometers physically separated by 35 meters, Europhys., Lett. 40, 595 (1997)Google Scholar
  41. 37.
    M.A. Horne, A. Shimony, A. Zeilinger, Two-particle interferometry, Phys. Rev. Lett. 62, 2209 (1989)ADSCrossRefGoogle Scholar
  42. 38.
    J.G. Rarity, P.R. Tapster, Experimental violation of Bell’s inequality based on phase and momentum, Phys. Rev. Lett. 64, 2495 (1990)ADSCrossRefGoogle Scholar
  43. 39.
    W. Tittel, J. Brendel, H. Zbinden, N. Gisin, Violation of Bell inequalities by photons more than 10 km apart, Phys. Rev. Lett. 81, 3563 (1998)ADSCrossRefGoogle Scholar
  44. 40.
    M.A. Rowe, D. Kielpinsky, V. Meyer, C.A. Sackett, W.M. Itano, D.J. Wineland, Experimental violation of a Bell’s inequality with efficient detection, Nature 409, 791 (2001)ADSCrossRefGoogle Scholar
  45. 41.
    The interest of an active rather than a passive switching of the polarizers is questioned in: N. Gisin, H. Zbinden, Bell inequality and the locality loophole: active versus passive switches, Phys. Lett. A 264, 103 (1999)Google Scholar
  46. 42.
    G. Weihs, T. Jennewein, C. Simon, H. Weinfurter, A. Zeilinger, Violation of Bell’s inequality under strict Einstein locality condition, Phys. Rev. Lett. 81, 5039 (1998)MathSciNetADSCrossRefzbMATHGoogle Scholar
  47. 43.
    A. Aspect, Bell’s inequality test: more ideal than ever, Nature 398, 189 (1999)ADSCrossRefGoogle Scholar
  48. 44.
    For a scheme that could be ideal, using entangled atoms, see the paper of E. Fry in this bookGoogle Scholar
  49. 45.
    J.S. Bell, Atomic cascade photons and quantum-mechanical nonlocality, Comm Atom. Mol. Phys. 9, 121 (1981)Google Scholar
  50. 46.
    A. Aspect, Expériences basées sur les inégalités de Bell, J. Phys. Coll. C 2, 940 (1981)Google Scholar
  51. 47.
    C.H. Bennet, G. Brassard, C. Crépeau, R. Josza, A. Peres, W.K. Wootters, Phys. Rev. Lett. 70, 1895 (1993)MathSciNetADSCrossRefGoogle Scholar
  52. D. Bouwmeester, J.-W. Pan, K. Mattle, M. Eibl, H. Weinfurter, A. Zeilinger, Experimental quantum teleportation, Nature 390, 575 (1997)ADSCrossRefGoogle Scholar
  53. D. Boschi, S. Branca, F. De Martini, L. Hardy, S. Popescu, Experimental realization of teleporting an unknown pure quantum state via dual classical and Einstein—Podolsky—Rosen channels, submitted to Phys. Rev. Lett. (1997) A. Furusawa, J.L. Sorensen, S.L. Braunstein, C.A. Fuchs, H.J. Kimble, E.S. Polzik, Unconditional quantum teleportation, Science 282, 706 (1998)CrossRefGoogle Scholar
  54. 48.
    S. Popescu, Bell’s inequalities versus teleportation: what is non-locality? Phys. Rev. Lett. 72, 797 (1994)ADSCrossRefzbMATHGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Alain Aspect

There are no affiliations available

Personalised recommendations