  The inversion states of a saturated traveling-wave three-level quantum
paramagnetic amplifier have been investigated under conditions of bistable
resonator pumping. The equations of motion for the vectorial order parameter
have been obtained using adiabatic elimination of fast variables. The exact
solutions for stationary inversion states have been found from these equations.
For high-quality pump resonators, the isolated and the semi-isolated branches
of the inversion ratio have been revealed in stationary solutions. The
existence of the semi-isolated branches means a possibility of collapse of the
inversion state under influence of a saturating signal. Revival of inversion is
possible in this case only by the hard excitation of the pump system. This
nonlinear phenomenon is of a qualitatively another nature than one described by
us in arXiv:0901.0449v1 [nlin.AO], and may be observed at moderate Q-factor of
pump resonator.

Exactly Solvable and Integrable Systems;Other Condensed Matter;Optics