Nobel Prize in Physics Is Awarded to 3 Scientists for Work Exploring Quantum Weirdness

The catch in Dr. Clauser’s discovery and the quantum mechanical description of this spooky action was that the correlations only showed up after the measurements of the individual particles, when the physicists compared their results after the fact. Entanglement seemed real, but it could not be used to communicate information faster than the speed of light.

Dr. Clauser spent much of the decade worrying about what loopholes he might have overlooked. One possibility, which was called the locality loophole, was that the laboratory instruments might have been leaking information to each other.

Enter Dr. Aspect, who is now a professor at Université Paris-Saclay, in Paris, and École Polytechnique in Palaiseau, France. In the 1970s, on the way to his doctorate, he spent three years performing his national service requirement by teaching in Cameroon, boning up on quantum mechanics in his spare time. In an interview with the Nobel committee, he said he had returned to France ready to tackle the challenge posed by Dr. Bell’s work.

In 1982, Dr. Aspect and his team at the University of Paris tried to outfox Dr. Clauser’s loophole by switching the direction along which the photons’ polarizations were measured every 10 nanoseconds, while the photons were already in the air and too fast for them to communicate with each other. He too, was expecting Einstein to be right.

Dr. Aspect’s results put entanglement on the map as a real phenomenon that physicists and engineers could use. Quantum predictions held true, but there were still more possible loopholes in the Bell experiment that Dr. Clauser had identified and which needed to be closed before quantum physicists could declare victory over Einstein.

For example, the polarization directions in Dr. Aspect’s experiment had been changed in a regular and thus theoretically predictable fashion that could be sensed by the photons or detectors.

It was then that Anton Zeilinger — a professor at the University of Vienna, who with his group has emerged as perhaps the leading ringmaster of quantum trickery — picked up the baton. In 1998, he added even more randomness to the Bell experiment, using random number generators to change the direction of the polarization measurements while the entangled particles were in flight.

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