PhysOrg.com December 2, 2011

In the quantum world, diamonds can communicate with each other



“Researchers working at the Clarendon Laboratory at the University of Oxford in England have managed to get one small diamond to communicate with another small diamond utilizing ‘quantum entanglement,’ one of the more mind-blowing features of quantum physics.1


“Entanglement has been proven before but what makes the Oxford experiment unique is that concept was demonstrated with substantial solid objects at room temperature.  Previous entanglements of matter involved submicroscopic particles, often at cold temperatures. . . . When zapping one artificial diamond with ultrashort laser pulses they managed to change the vibrations of a second diamond sitting a half a foot away without touching it.


“Entanglement originated in the mind of Albert Einstein, who ironically came up with the notion trying to disprove quantum mechanics, a branch of physics he mistrusted all his life.  Under the theory, if two particles, say electrons, are created together, some of their attributes will become ‘entangled.’ If the two are then separated, doing something to one instantly affects the other. This would happen whether they were next to each other or across the universe. . . .


“This would mean that the information about the change traveled faster than the speed of light –– which Einstein said was impossible –– or that long distances are some kind of illusion. . . .


“The diamonds [Ian] Walmsley and his international team used were approximately 3 millimeters (a tenth of an inch) square and 1 millimeter thick.  ‘We used short pulse lasers with pulse durations of around 100 femtoseconds (a quadrillionth of a second). A femtosecond is to a second as a nickel is to the debt of the federal government generally speaking, he said.  They chose diamonds because they are crystals, so it was easier to measure molecular vibrations, and because they are transparent in visible wavelengths. Light from the lasers altered a kind of mass vibration in the diamond crystal called phonons, and the measurements showed they were entangled: The vibrations of the second diamond reacted to what happened to the vibrations of the first.


Performing the experiment with ultrafast laser pulses enabled the researchers to catch entanglement, which is usually very short-lived in large objects at room temperature.







1  Cf. K.C. Lee et al., Entangling Macroscopic Diamonds at Room Temperature,Science 2 December 2011: Vol. 334 no. 6060 pp. 1253−1256.  Online.  Available at: http://www.scribd.com/doc/74558316/Entangling-Macroscopic-Diamonds-at-Room-Temperature.  December 2011.  See also, on this web, Special Relativity Beyond the Speed of Light and Neutrinos Faster than Light?









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