May 22, 2013

MACRO, NOT JUST MICRO:

When shining a light is a problem in itself : Heisenberg's uncertainties are starting to cause problems for some very big experiments (Steve Jones, 21 May 2013, The Telegraph)

In science, as in life, the old jokes are the best. The physicist Werner Heisenberg was once stopped for speeding. "Professor Heisenberg," the cop said, "do you know how fast you were going?" "No," he replied, "but I know exactly where I am!" [...]

All that may seem irrelevant to daily life. But now the mechanical effect of light has been found to influence things on what, to a physicist, is a gigantic scale (or, at least, can almost be seen with the naked eye). It's a tiny membrane that acts as a mirror and is vibrated fast. Shine a laser beam on it, and suddenly the mirror begins to shake even more violently, and in an unpredictable way. The energy of the photons means, once again, that the reflected light beam cannot be used to give a precise picture of both the position and the speed of movement of the mirror's surface, just as Heisenberg predicted.

Posted by at May 22, 2013 2:35 PM
  

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