NONPERTURBATIVE PRODUCTION OF MULTIBOSON STATES AND QUANTUM BUBBLES

The amplitude of production of n on-mass-shell scalar bosons by a high ly virtual field phi is considered in a lambdaphi4 theory with weak co upling lambda and spontaneously broken symmetry. The amplitude of this process is known to have an n! growth when the produced bosons are ex actly at rest. Here it is shown that for n >> 1/lambda the process goe s through ''quantum bubbles,'' i.e., quantized droplets of a different vacuum phase, which are nonperturbative resonant states of the field phi. The bubbles provide a form factor for the production amplitude, w hich rapidly decreases above the threshold. As a result the probabilit y of the process may be heavily suppressed and may decrease with energ y E as exp(-const X E(a)), where the power a depends on the number of space dimensions. Also discussed are the quantized states of bubbles a nd the amplitudes of their formation and decay.