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Light particles communicate over six miles

12:41 PM ET 06/26/97


LONDON (Reuter) - What Albert Einstein described as a "spooky'" quality of light just gets spookier, according to Swiss scientists.

They have found evidence that light particles known as photons are somehow linked over a distance of six miles, New Scientist magazine reported Thursday.

It said Nicolas Gisin and colleagues at the University of Geneva generated pairs of photons and sent them along two separate optic fibers, ending up six miles apart.

Physicists say the quality could help explain how light manages to act like a wave and a flow of particles at the same time.

Using the well-known law of physics that measuring a particle affects it, they determined that measuring one photon also affected the other.

There was no way the two photons could have communicated over such a distance, meaning they must have been ``entangled,'' Gisin said.

Einstein predicted this would happen more than 60 years ago, but called the idea ``spooky action at a distance'' and thought it was a flaw in his quantum theory.

Alain Aspect and colleagues at the University of Paris first showed that this does indeed happen, but in particles no more than a few yards apart.

"Gisin's experiment is really significant because he shows that he can maintain these amazing quantum correlations over a very long distance,'' Aspect told New Scientist.

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