When Atoms Behave as Waves: Bose–Einstein Condensation and the Atom Laser (Nobel Lecture)

Atom plus atom equals…︁ vacuum! The destructive interference of atoms is just one of the surprising effects of coherent atoms. The long and winding road from trapping atoms to the atomic laser, passing the peak of the Bose – Einstein condensate, won Ketterle a share in the 2001 Nobel Prize for Physics. The graphic shows pulses of coherent sodium atoms (each containing 105 – 106 atoms produced every 5 ms) falling under gravity and expanding due to mutual interatomic repulsion.