The multi-connected momentum distribution and fermion condensation

The structure of the ground state beyond the instability point of the quasi particle system with a Fermi-step momentum distribution is studied within t he model of a Fermi liquid with a strong repulsive interaction. A ground-st ate rearrangement occurs as the interaction strength is increased beyond a certain critical value. Numerical investigation of the initial stage of thi s structural transition shows that there are two temperature regions, corre sponding to different scenarios of the rearrangement. While for temperature T larger than some characteristic temperature To the behaviour of the syst em is the same as that in the case of fermion condensation, for T less than or similar to T-0 an intermediate structure with a multi-connected quasipa rticle momentum distribution arises.