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Alain Aspect
Born 15 June 1947
Agen, France
Residence France
Nationality French
Fields Physicist
Institutions SupOptique
Ecole Polytechnique
Centre national de la recherche scientifique
Alma mater École Normale Supérieure de Cachan
Known for Bell test experiments

Alain Aspect (About this sound aspect.ogg born 15 June 1947 in Agen) is a French physicist and alumnus of the École Normale Supérieure de Cachan (ENS Cachan) in France. In the early 1980s, with collaborators in France, he performed the crucial "Bell test experiments" that showed that Albert Einstein, Boris Podolsky and Nathan Rosen's reductio ad absurdum of quantum mechanics, namely that it implied 'ghostly action at a distance', did in fact appear to be realised when two particles were separated by an arbitrarily large distance. A correlation between their wave functions remained, as they were once part of the same wave-function that was not disturbed before one of the child particles was measured.

If quantum theory is correct, the determination of an axis direction for polarisation measurement of one photon, forcing the wave function to 'collapse' onto that axis, will influence the measurement of its twin. This influence occurs despite any experimenters not knowing which axes have been chosen by their distant colleagues, and at distances that disallow any communication between the two photons, even at the speed of light.

Aspect's experiments were considered to provide overwhelming support to the thesis that Bell's inequalities are violated in its CHSH version. However, his results were not completely conclusive, since there were so-called loopholes that allowed for alternative explanations that comply with local realism. See local hidden variable theory.

Stated more simply, the experiment provides strong evidence that a quantum event at one location can affect an event at another location without any obvious mechanism for communication between the two locations. This has been called "spooky action at a distance". However, these experiments do not allow faster-than-light communication, as the events themselves appear to be inherently random.

After his works on Bell's inequalites, he turned toward studies of laser cooling of neutral atoms and is now mostly involved in Bose-Einstein condensates related experiments.

Aspect was deputy director of the French "grande école" SupOptique until 1994. He is a member of the French Academy of Sciences and French Academy of Technologies, and professor at the Ecole Polytechnique. In 2005 he was awarded the gold medal of the Centre national de la recherche scientifique, where he is currently Research Director.

Selected bibliography

  • Experimental Realization of Einstein-Podolsky-Rosen-Bohm Gedankenexperiment: A New Violation of Bell's Inequalities, A. Aspect, P. Grangier, and G. Roger, Physical Review Letters, Vol. 49, Iss. 2, pp.91-94 (1982) doi:10.1103/PhysRevLett.49.91
  • Experimental Test of Bell's Inequalities Using Time-Varying Analyzers, A. Aspect, J. Dalibard and G. Roger, Physical Review Letters, Vol. 49, Iss. 25, pp. 1804-1807 (1982) doi:10.1103/PhysRevLett.49.1804
  • To be or not to be local, A. Aspect, Nature, Vol. 446, pp. 866-867 (2007)

See also

External links

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Quotes

Up to date as of January 14, 2010

From Wikiquote

Alain Aspect (born June 15, 1947) is a French physicist who performed the crucial "Bell test experiments" that showed that Albert Einstein, Boris Podolsky and Nathan Rosen's "spooky action at a distance", did in fact appear to be realised when two particles were separated by an arbitrarily large distance. A correlation between their wave functions remained, as they were once part of the same wave-function that was not disturbed before one of the child particles was measured.

Sourced

  • Certainly we do not need quantum mechanics for macroscopic objects, which are well described by classical physics – this is the reason why quantum mechanics seems so foreign to our everyday existence.
    • in the introduction of John Stewart Bell's Speakable and Unspeakable in Quantum Mechanics, 2nd edition. Cambridge University Press. 2004. p. xxix. ISBN 0521523389.  
  • La principale difficulté pour vulgariser la physique quantique, c'est qu'on ne sait pas très bien comment en fabriquer des images dans notre monde. C'est en ce sens qu'elle est vraiment contre-intuitive.
    • The main difficulty in popularizing quantum physics is that we do not really know how to make images of it in our world. In this sense it is really counterintuitive.
    • Interview on the occasion of the CNRS Gold Medal Award Ceremony in December 2005.

External links

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