A Bose Einstein Condensate in Helium

A Bose Einstein condensate (BEC) in helium has been made in two separate French Labs. Previously BECs have only been made with alkali atoms and with hydrogen, and in these cases the atoms were in their ground states. This time around, with noble helium, the atoms are in an excited state, the better to control them; the price for using such excited atoms (each with 20 electron volts of internal energy) is that it is difficult to gather a large ensemble of atoms together. Nevertheless, Alain Aspect's group at the CNRS lab of the Institut d'Optique at Orsay produced a helium BEC and detected the atoms, one by one, by having them fall onto a microchannel plate (Science 23 March).

Meanwhile Claude Cohen-Tannoudji's group at the Ecole Normale Superieure imaged their helium condensate using more conventional camera techniques (Pereira Dos Santos et al., upcoming article in Physical Review Letters: text at Physics News Select, contact Franck Pereira Dos Santos, pereira@lkb.ens.fr). One possible application of such excited-state BECs is that atoms emerging from a prospective atom laser could be manipulated for performing some kind of atom lithography.