  Recently, in high-T_c superconductors (HTSC), exciting measurements have been
performed revealing their physics in superconducting and pseudogap states and
in normal one induced by the application of magnetic field, when the transition
from non-Fermi liquid to Landau Fermi liquid behavior occurs. We employ a
theory, based on fermion condensation quantum phase transition which is able to
explain facts obtained in the measurements. We also show, that in spite of very
different microscopic nature of HTSC, heavy-fermion metals and 2D 3He, the
physical properties of these three classes of substances are similar to each
other.
