[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!

[bvw]

You worked with extremely cold stuff? Liquid He and all that?