Starting with a time-independent Hamiltonian h and an appropriately chosen
solution of the von Neumann equation iΟΛβ(t)=[h,Ο(t)] we construct
its binary-Darboux partner h1β(t) and an exact scattering solution of
iΟΛβ1β(t)=[h1β(t),Ο1β(t)] where h1β(t) is time-dependent and not
isospectral to h. The method is analogous to supersymmetric quantum mechanics
but is based on a different version of a Darboux transformation. We illustrate
the technique by the example where h corresponds to a 1-D harmonic
oscillator. The resulting h1β(t) represents a scattering of a soliton-like
pulse on a three-level system.Comment: revtex, 3 eps file