Atom lasers are gonna be mighty useful for testing quantum mechanics to its limits. But ain’t nobody built one that can operate continuously, which is what yerl need for these kindsa experiments. We’ve had pulsed atom lasers for about a decade and it looks as if a continuous version may be close.
Atom lasers work by cooling a pile ‘o’ atoms so that they occupy the same quantum state, watcha call a Bose Einstein Condensate (BEC) . Then ya allow the condensate to ‘drip’ so that it releases a constant stream of coherent atoms in the same state. But a BEC contains a limited number of atoms so as it drips, the reservoir of atoms has to be replenished. The trouble is that BECs are incredibly fragile, sneeze and they disappear in puff o’ smoke. So physicists have been a-puzzlin’ and a-wondrin’ over how to do the replenishin’.
Now Nick “Dun” Robins at the Australian National University in Canberra says he and a few mates have worked out how to do it by pumping atoms into the BEC from a physically separate cloud nearby. That allows their laser to operate continuously, at least in theory. In practice, they can’t tell whether the laser is actually working cos it produces too few atoms to count.
That’s not a huge barrier to overcome and it should be straightforward to hit the jackpot soon. But that raises the questions: why release these results now? Obviously Robins wants to get them out there before his team is pipped to the post by somebody else.
So sometime soon we can expect to hear somebody (but not necessarily Robins) announce they built of the first continuous pumped atom laser.
Ref: arxiv.org/abs/0711.4418: A pumped atom laser