It was announced yesterday that Alain Aspect, John Clauser and Anton Zeilinger have been jointly awarded the Nobel prize in physics for their experiments to test the effects of quantum entanglement. These experiments are both extremely important and extraordinarily difficult.
The story can be said to begin with the famous Einstein-Podolsky-Rosen paper of 1935 where they seemed to suggest that the theory of quantum mechanics, by then already hailed as a massive success, had to be incomplete because there were elements of reality that were not represented in the theory. In their paper, they argued that in the standard Copenhagen interpretation of quantum mechanics that was embraced by most physicists, one could have situations where a measurement made on one particle could instantaneously influence the outcomes of a measurement on another particle however far away it was. Einstein felt that was ‘spooky’.
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