Physicists Seek Answers to Quantum Correlations
Physicists sent two photons down optical fibers toward different destinations, and found that the photons could instantly sense each other's behavior.
After performing multiple tests on two entangled photons, physicists have yet again found that the photons seem to be communicating faster than the speed of light - at least 100,000 times faster. The researchers hope that their results might encourage theorists to come up with new explanations for the strange quantum mechanical effect.
The physicists, led by Nicolas Gisin from the University of Geneva, arranged their experiment by sending two photons down fiber optic cables to detectors in two Swiss villages located 18 km apart. Both photons started in Geneva, with one heading toward Satigny and the other toward Jussy. The study, which is published in Nature, builds on previous tests published a few months ago in Physical Review Letters.
When the researchers measured several properties of each photon at its destination, they found that the particles could instantly sense the otherīs behavior without any known communication. Although this correlation obeys the laws of quantum mechanics, it seems to defy the nature of space and time, at least from humansī everyday perspectives.
The physicists ruled out several possible classical explanations for the instantaneous communication. For one thing, they showed that the photons did not share information before leaving Geneva, and so they didnīt travel knowing about each otherīs properties.
In another test, the scientists showed that no communication could have occurred through a different reference frame, as might happen because of the photonsī high speeds. According to Einsteinīs theory of relativity, observers moving at high speeds can get different measurements of the same event because they have different reference frames. But, by performing tests over a complete rotation of the Earth, the researchers ruled out this possibility.
For now, Gisinīs team doesnīt have a good explanation as to how the seemingly instant correlations happen. Even though it doesnīt make sense to them, they hope that others might one day find a better understanding.
In a Nature News story, theorist Terence Rudolph at Imperial College London suggested that humans think that the three dimensions of space and one dimension of time that weīre used to should be the same everywhere, on all scales. But, he says, some things in quantum mechanics might transcend our view of space-time, and we just donīt get to see the whole picture.
"We think space and time are important because thatīs the kind of monkeys we are," he said.
More information: Salart, D., Baas, A., Branciard, C., Gisin, N. & Zbinden, H. Nature, 454, 861-864 (2008).
via: Nature News
When the researchers measured several properties of each photon at its destination, they found that the particles could instantly sense the otherīs behavior without any known communication. Although this correlation obeys the laws of quantum mechanics, it seems to defy the nature of space and time, at least from humansī everyday perspectives.
The physicists ruled out several possible classical explanations for the instantaneous communication. For one thing, they showed that the photons did not share information before leaving Geneva, and so they didnīt travel knowing about each otherīs properties.
In another test, the scientists showed that no communication could have occurred through a different reference frame, as might happen because of the photonsī high speeds. According to Einsteinīs theory of relativity, observers moving at high speeds can get different measurements of the same event because they have different reference frames. But, by performing tests over a complete rotation of the Earth, the researchers ruled out this possibility.
For now, Gisinīs team doesnīt have a good explanation as to how the seemingly instant correlations happen. Even though it doesnīt make sense to them, they hope that others might one day find a better understanding.
In a Nature News story, theorist Terence Rudolph at Imperial College London suggested that humans think that the three dimensions of space and one dimension of time that weīre used to should be the same everywhere, on all scales. But, he says, some things in quantum mechanics might transcend our view of space-time, and we just donīt get to see the whole picture.
"We think space and time are important because thatīs the kind of monkeys we are," he said.
More information: Salart, D., Baas, A., Branciard, C., Gisin, N. & Zbinden, H. Nature, 454, 861-864 (2008).
via: Nature News
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