What is Bose-Einstein condensation good for? It is too new and we know too little about it for me to give you an answer. It is much the same as if I were living in Tahiti 400 years ago and a freak iceberg washed up on the shore. Having never seen ice before, it would be a while before I or anyone else would realize that it could be used to make ice cream! There are also some engineering problems that will have to be solved before BEC can be used for very much. What sort of problems? Well, first it is incredibly fragile. It is the most fragile thing that has ever existed! Second, physicists are still making very small quantities of it, only a few million atoms at a time. Finally, they can only make it out of a few different types of atoms. However, physicists will certainly figure out how to make more and different kinds, and handle it carefully enough to keep it around. Still, that doesn't mean it will be useful for anything. No, you are right; it doesn't. However, the similarities between BEC and laser light suggest that it probably will be. What makes laser light different from ordinary light is that all the photons are exactly the same. They are the same color and they are all going in the same direction. It is this "specialness" that allows us to do all sorts of neat things with laser light, because it means we can control laser light so much better than we could old fashioned light from light bulbs. BEC shares this same "specialness" with laser light. All the atoms in the condensate are exactly the same. So this means that we now have much better control over atoms: where they are and how fast they are moving. In fact, we now can control them as well as the uncertainty principle will allow. From the similarities with laser light, it is a pretty good bet that some day BEC will be good for making very sensitive measurement instruments and maybe making tiny structures, like they use in computer chips. So should I start investing in BEC companies? Maybe not right away. Remember, it took twenty years after their invention before people started to realize how lasers could be useful. Now forty years later they are being used in your grocery store, your dentist's office, and to make your telephone work. So you will probably have to wait a few years before BEC gets used very much outside the research lab.

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