Coherent boson states

An analysis is made of the condition for stimulated precipitation of Bose particles to form a coherent Bose condensate. Experimental observations of the interference of Bose condensates are described. A system of equations is proposed for the dynamics of a generator of coherent atomic beams, i.e. an ‘atom laser’. This system of equations takes account of the interaction of a Bose condensate with incoherent particle subsystems. A description is given of experimental observations of stimulated amplification of an exciton bunch. The possibility of generation of a coherent state of excitons by direct binding of free carriers in semiconductors and insulators is considered.