Saturday, 24 November 2007

Small World: Quantum Identity Crisis Observed

A quantum enigma has been put to the test once again, but this time physicists have made the experiment smaller than it has ever been.

The classic double-slit experiment tests the behavior of light, electrons, atoms and some molecules as both particle-like and wave-like, a mysterious duality that has intrigued and puzzled scientists for more than a century.

Light or electrons are aimed at a solid plate with two parallel cuts in it, offering two choices: go through the slit on the left or the slit on the right. Subatomic particles will sometimes break the rules and go through both slits, just as a wave would.

The most bizarre aspect of this particle-wave duality is that it depends on how much an observer pays attention. The more carefully the observer measures whether it was the left or right slit, the more the object in question chooses a single slit, just as a particle would.

Now an international team of scientists has exhibited this quantum identity crisis using a single hydrogen molecule as their lab equipment.

Click here for full Live Science article

1 comment:

Marc said...

Interesting story but what puzzles me is that they are not relying on human observers to affect the path of the electron but that of one of the other paired electrons - which is odd don't you think? i.e. does an electron observe?
"If the slow electron had little energy, it had trouble measuring the fast electron's movement. As a consequence, the fast electron went through both slits like a wave. But if the slow electron had more energy, it got a good look at the fast electron, which responded by choosing one slit like a particle."