One Particle, Two Worlds

By Susan Kruglinski|Sunday, June 27, 2004
RELATED TAGS: SUBATOMIC PARTICLES

In some ways, the world seems divided in two: our classical world, where objects have well-defined locations, and the quantum realm, where particles seem to be everywhere at once. University of Vienna physicists designed an experiment to traverse these worlds with a change in temperature.

Courtesy of Dr. Robin Riegler

A hot laser in Vienna probes the bounds of quantum physics.

Using a laser, Anton Zeilinger, Markus Arndt, and their team heated giant carbon molecules to more than 5,000 degrees Fahrenheit in an airless environment. Above that temperature the molecules acted in a classical way. But as the temperature dropped, they switched into a wavelike state in which their location could be described only in the statistical terms of quantum physics—they no longer seemed to be in any one place. This transition may depend not on temperature but on the particle’s relationship to its surroundings. When the carbon molecule was hot, it emitted radiation that interacted with nearby walls, giving it a definite location. When cooled, the molecule stopped radiating and became an isolated quantum-style object.

The transition from quantum to classical, called decoherence, has never before been demonstrated by using heat. The work could have a big payoff. Researchers worldwide are attempting to control decoherence to build a quantum computer that, if perfected, could lead to unbreakable encryption and ultrafast information processing.

Comment on this article
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT
ADVERTISEMENT
Collapse bottom bar
DSCJulyAugCover
+

Log in to your account

X
Email address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it emailed to you.

Not registered yet?

Register now for FREE. It takes only a few seconds to complete. Register now »