All together now

A “LASER” beam of atoms is almost within physicists’ grasp. Just as optical lasers produce a beam of photons, atom lasers fire out a stream of matter from a Bose-Einstein condensate, a cloud of atoms so cold that they behave as a single wave. So far, these beams can only be produced in pulses, as the condensate cloud quickly runs out. Now Ananth Chikkatur and colleagues at MIT have used “tweezers” of focused laser light to top up an existing atom cloud by adding fresh condensate. The technique could eventually allow researchers to produce strong, continuous atom lasers, Chikkatur says. The researchers publish their results in a future issue of Science.…