[nasamn777]

Your link says:

That sounds like quite a trick.

It is. It took physicists quite a while to figure out how to do it. (Click here to find out more about laser cooling and the winner of the 1997 Nobel Prize for Physics.) You start with the idea that laser light comes in a stream of photons. These photons are very light, so to speak. Compared to an atom, they are like ping-pong balls compared to a bowling ball. But in just the same way you can push a bowling ball around if you shoot a big enough stream of ping-pong balls at it, you can push atoms around by bouncing laser light off them. Try to adjust the laser power and laser position to slow down the atoms.

What happens to the light that bounces off the surface? Ultimately it will contact a surface and be absorbed!

[Right Wing Professor]

What happens to the light that bounces off the surface? Ultimately it will contact a surface and be absorbed!

...just as the light energy from the sun is eventually radiated to space and attains a very low temperature. So the laser decreases the entropy of the condensate, just as the sun decreases the entropy of living systems.

[grey_whiskers]

Question about the laser cooling, RWP. Since the vibration is quantized, do they take care to use laser light such that each photon holds one vibrational quantum of energy for that material? Or do they use much lower energy photons (the bowling ball analogy sounds awfully classical BTW !!) and make sure the photons arrive at the right point in the vibrational 'phase' so that the nucleus of the relevant atom is heading more or less in the opposite direction to the incoming photon? Just point me to a website with more details if you don't feel like answering :-) Thanks!