On kinematics and dynamics of independent pion emission

Multiparticle boson states, proposed recently for 'independently' emitted pions in heavy ion collisions, are reconsidered in standard second quantized formalism and shown to emerge from a simplistic chaotic current dynamics. Compact equations relate the density operator, the generating functional of multiparticle counts, and the correlator of the external current to each other. 'Bose-Einstein-condensation' is related to the external pulse. A quantum master equation is advocated for future Monte-Carlo simulations.