ANOTHER COOL IDEA FROM TEXAS (Physicists at UT Discovered "quantum refrigerator" to Cool Atoms)

U-WIRE | Aug. 10, 2005 | Amanda Pinkston

[nickcarraway]

Physicists at the University of Texas have discovered the "quantum refrigerator," which might prove to be the next big breakthrough in atom-cooling.

No, it can't chill a beer, but this "refrigerator" can drop the temperature of a wide range of atoms and particles to nearly absolute zero – -459 degrees Fahrenheit – allowing scientists to better control the atom's motion.

The current atom-cooling techniques are laser cooling, which was realized experimentally in the 1980s and resulted in a Nobel Prize in 1997, and evaporative cooling, which resulted in a Nobel Prize in 2001. The methods are limited, however, because they depend on a closed "cycling" transition – an atom's return to its original state after being excited to an elevated state. But most atoms and particles do not return to their original state, and only a handful can currently be cooled.

Mark Raizen, of the Center for Nonlinear Dynamics, came up with the refrigerator idea in 2004 in his search for alternative cooling methods that would work for atoms and molecules with more complicated structures and therefore one that did not rely on the cycling transition.

First came his idea for a barrier made from light that would allow atoms to pass through on one side by hitting them with a beam that changes their state but reflects them on the other side where they are not hit by the state-changing beam. Raizen got his idea from an object similar in concept to one found in nature: The one-way ion-channels found in cell membranes.

Ions can travel through the membrane into the cell but are then unable to escape, despite unequal pressures in and outside of the cell. He used the cell membrane concept in tandem with the fact that light can exert force on matter, a theory first proposed in 1619, to develop the one-way atom barrier made of light beams.

Next was the cooling method. Particles are trapped in a box with walls made of light. Then, the one-way barrier is turned on inside of the box, and the particles on the transmission side pass through, confining all the particles to a smaller area. The wall is then moved across the box towards the particle-free side. As the particles bounce off the wall that is moving away from them, they lose kinetic energy, which is heat, and loss of heat means a cooler particle. Repetition of this process will eventually cool the particles to near absolute zero.

Raizen said he hopes that this theory will lead to experiments by groups that specialize in atom cooling and, if proved successful, become an adopted method to cool particles. "Ultimately," he said, "the goal is to cool all atoms in the periodic table."

[martin_fierro]

I'm guessin' this has nothing to do with RFID.

< |:)~

[grey_whiskers]

I'd have been more excited (bad pun) if it had come of out anywhere but Texas.

Otherwise, COOL! (sorry, just can't help myself).

Cheers!

[grey_whiskers]

Science type PING!

[TADSLOS]

No, it can't chill a beer...

Then, what good is it?

[snarks_when_bored]

Thanks for the ping, g_w. It sounds as if Maxwell's Demon has come a bit closer to incarnation...

[RightWingAtheist]

Could this technique be applied to HEP, as a means of isolating particles after collisions for study, or in experimental astrophysics, as a means of studying cosmic rays and other spaceborn massive particles?

[RightWingAtheist]

The Second Law stands, tho :)

[snarks_when_bored]

The Second Law stands, tho :)

Yep.

[SunkenCiv]

related:

Laser Cooling
Department of Physics and Astronomy, Georgia State University
post-1985 | Carl R. (Rod) Nave
Posted on 12/28/2004 9:57:07 AM PST by SunkenCiv
http://www.freerepublic.com/focus/f-bloggers/1309656/posts

[SunkenCiv]

science stuff ping.