Bose Condensates Produce Coherent Nonlinear Behavior

Because the atoms in a gaseous Bose condensate have nearly the same single‐particle wavefunction, they can serve as sources of coherent atomic beams, or atom lasers. In analogy to an optical laser, the gain mechanism in the formation of a condensate of ultracold atoms is bosonic stimulation. (Bosonic stimulation occurs when N bosons are in a given state, and the transition rate into that state is proportional to $N+1,$ so that the number of particles in that state is enhanced.)